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| Technical Assistance Tips The following technical tips provide repair information about specific conditions on a variety of vehicles. If you have a tough or unusual service repair, the ACDelco Technical Assistance Centre (TAC) can help. Call 1-800-263-3526, Prompt 2 to speak with a technical expert with the latest OEM information. New Design Cylinder Heads - January 2012 2007-2009 Pontiac G6, Saturn AURA; 2007-2010 Saturn OUTLOOK; 2007-2011 Cadillac CTS, Cadillac SRX, Cadillac STS, GMC Acadia, Buick LaCrosse; 2008-2009 Pontiac G8; 2008-2010 Saturn VUE; 2008-2011 Buick Enclave, Chevrolet Malibu, Chevrolet Equinox; 2009-2011 Chevrolet Traverse; 2010-2011 Chevrolet Camaro; equipped with the 3.6L (RPO LY7, LLT), 2.8L (RPO LAU) or 3.0L (RPO LF1, LFW) V6 engine. When replacing cylinder heads on a High-Feature V6 engine, do not use shims/spacers with the 2011 new style “saddle cap” cylinder head. Use of shims/spacers on this head can cause damage to the cylinder head and actuators. Also, the camshaft actuators specifically for the new design head for your application must be used. The new saddle cap design cylinder heads will not work with the 2004-2006 engines and first design 2007 engines. All timing components and calibrations are different. Replacement Oil Filter - December 2011 2011 Chevrolet Equinox and GM Terrain equipped with 3.0L engine (RPO LFW); 2011 Buick Enclave, Buick LaCrosse, Chevrolet Traverse and GMC Acadia equipped with 3.6L engine (RPO LLT)
GM recommends service replacement oil filter PF63 (P/N 89017525) in order to provide more filter media for additional filtration and strength. This is a new filter replacement for high-feature V6 applications, changing from PG48. The replacement oil filter (PF63) is longer than the OEM production filter. ACDelco oil filters are designed to meet the manufacturer’s specifications for modern GM powertrains that have higher engine oil pressures, increased oil flow rates and extended oil change intervals in both cold and warm operating conditions. It may be difficult to remove the longer replacement oil filter (PF63) without bottoming the filter end cap wrench on the auxiliary cooling fan housing on Terrain and Equinox models. It may be necessary to remove the oil filter end cap wrench after loosening the filter, yet prior to un-threading the filter from the engine adapter. The PF63 filter should be installed and hand tightened. Then if additional torque is needed, install the filter end cap wrench and torque to specification. Manual Transmission Service Tips - November 2011 When performing service on a manual transmission, keep in mind the following tips regarding transmission operation. Auxiliary Fluid Cooler Also, if the transmission flow/flush machine has Dexron VI in it, remember that Dexron VI is not compatible with manual transmissions. It will be necessary to thoroughly drain the oil cooler and lines before re-installing them to the transmission. Synchronizers
Diesel Engine Ticking Noise - October 2011 Some diesel engines may exhibit a random ticking noise that is most audible on an engine with a coolant temperature of 70 degrees census or higher and from idle to approximately 1500 rpm. The noise usually is most noticeable at the rear of the driver’s side front wheel well. A ticking noise also may be heard inside the vehicle at idle such as when sitting at a drive-through window. All 6600 Duramax diesel engines have this condition; however, some are more audible than others. Engine build variation from engine to engine contributes to differences in perceived volume. All Durmax engines are manufactured to very close tolerances to meet durability and reliability standards. This ticking noise is caused by the relationship of the engine cylinder block, crankshaft journals, bearing inserts and the oil film. This relationship may allow a vibration that resonates through the cylinder block and may be heard as an irregular metallic ticking noise. This condition has been present in diesel engines produced by many manufacturers for the last 20 or more years. The overall noise reduction in engines produced today makes this noise seem new when, in fact, it was masked by other noises in the past. Testing and engine teardowns with this condition reveal no condition that would affect reliability or durability of this engine. This noise is a normal operating characteristic of the engine. It has no short- or long-term effects on the engine. Replacing the engine or internal components for this noise will not reduce or eliminate the noise.
Passenger Presence System Indicator On Due to Electronic Devices - September 2011 When certain electronic devices, such as computers, MP3 players, cell phones, a scan tool, etc., are placed on the front passenger seat, the front passenger airbag indicator may illuminate. The seat belt reminder light/chime may also be activated. This is due to the fact that some electronic devices placed on the front passenger seat may interfere with the electric field generated by the Passenger Presence System (PPS) system, causing it to enable (turn On) the passenger airbag and turn on the safety belt reminder light and chime – even though the seat is not occupied. The electronic device does not necessarily need to be turned on to cause this condition. Several Diagnostic Trouble Codes also may set, depending on the vehicle. If the electronic device is removed from the front passenger seat, the DTC will go into history. If this happens, all Sensing and Diagnostic Module (SDM) and PPS DTCs should be cleared using a scan tool. If the DTC is still current, follow the service procedure in the GM Service Information for that DTC. Never rest the diagnostic scan tool or components on the passenger front seat or touch the passenger front seat while the diagnostic scan tool is in contact with your body. This may cause the SIR lamp to illuminate while holding the diagnostic scan tool because your body can transfer the electronic “noise” to the sensor mat in the passenger front seat. Advise customers to avoid placing the electronic device on the front passenger seat in the future.
Power Steering Fluid Restictor- August 2011 A rattle or knocking noise noticed when turning the steering wheel while driving slowly over rough roads may be caused by hydraulic noise within the steering rack. To correct this condition, install a fluid restrictor, part number 22592200, in the power steering return line. Remove the power steering return hose from the power steering pump. Install the fluid restrictor in the power steering fluid reservoir return port. The inlet and outlet hoses must not be twisted during installation. Do not bend or distort the inlet or outlet hoses to make installation easier. After installation, fill and bleed the power steering system.
Rear Leaf Spring Clunk Noise - June 2011 A rear leaf spring slap or clunk noise may be heard when the vehicle is operated over irregular road surfaces. The rear leaf spring tip inserts may have broken apart from wear and fallen out, or may be severely worn or damaged. Do not disassemble the main pack on the leaf spring or remove the bushing from the spring when diagnosing this condition. Verify that the rear leaf spring tip inserts are present on the leading and trailing ends of the overload spring (second stage leaf), and inspect the condition of the inserts. If the inserts are either not present or severely worn or damaged, install new inserts. On some models, the vehicle may have to be raised to allow the springs to separate enough so the insert can be installed. Vehicles originally equipped with plastic or plastic and rubber design tip inserts can be serviced by updated all rubber design inserts.
Noise when Turning while Driving over Rough Roads - May 2011 A rattle or knocking noise may be heard when turning the steering wheel while driving slowly over bumps. This condition may be caused by a hydraulic noise within the steering rack. Refer to GM Bulletin #03-02-32-002 for the service procedure to install a fluid restrictor in the power steering fluid reservoir return line. To install the fluid restrictor, the air cleaner intake tube must be removed, followed by the power steering return hose being removed from the power steering pump. The inlet and outlet hoses must not be twisted during installation. Bending the inlet or outlet hoses to make installation easier could lead to component damage.
Inoperative Heated Seat - April 2011 Heated Seats Heated/Cooled Seats
Air Cleaner Cover Installation - March 2011 2007-2011GMC Acadia, 2007-2010 Saturn OUTLOOK, 2008-2011 Buick Enclave, and 2009-2011 Chevrolet Traverse
It is possible for the washer hose assembly to become misrouted or trapped between the air cleaner cover and lower housing after air cleaner inspection or air cleaner element replacement. This may cause the washer hose to be pinched by the housing. When reassembling the air cleaner cover to the lower housing, ensure the windshield washer hose clip is secured to the cover and the hoses are routed properly before tightening the air cleaner cover screws.
Ball Joint Installation - February 2011 1999-2006 Cadillac Escalade ESV; Chevrolet Avalanche 3/4 ton, Suburban 3/4 ton, Silverado 1/2 ton HD, 3/4 ton and 1 ton, Express cab; HUMMER H2; GMC Sierra 1/2 ton HD, 3/4 ton and 1 ton, and Yukon XL models. Premature ball joint wear or control arm failure may result if the proper steps are not followed for ball joint removal, control arm inspection and ball joint installation. Before removing the existing ball joint from the control arm, inspect the ball joint housing for damage or excessive rust that would make ball joint replacement unacceptable. Never remove a ball joint by hammering or pressing out at an angle, which could damage the control arm. After ball joint removal, inspect the control arm for wear and elongation. If these conditions are found, the complete control arm assembly should be replaced. ACDelco offers a complete control arm assembly with the ball joint installed for repairs that require the assembly due to a problem with the control arm hole. If only the ball joint is being replaced, the ACDelco upper ball joint for these vehicles must have the ball joint housing properly indexed to the existing control arm prior to being pressed in. Because the ball joint is a directional type, the swing angle of the ball joint stud is limited in its range of motion. Incorrect orientation of the ball joint housing could cause premature ball joint wear or control arm failure. INSTALL INBOARD is stamped on the bottom of the upper ball joint. Install the words INSTALL INBOARD facing toward the engine compartment of the vehicle.
Duramax Diesel Glow Plug Replacement - January 2011 2006-2011 Duramax diesel engine (RPOs LMM, LGH, LML) After replacing a glow plug on a Duramax diesel engine, it may be noted that a P0671-P0678 DTC (glow plug control circuit DTCs for cylinders 1-8) will not clear. This is because the control module will not clear the DTC if the glow plugs are not energized during the next key cycle. A glow cycle is necessary to allow the GPCM to reset the glow plug resistance calculation, which will clear the DTC. The Glow Plug Control Module (GPCM) will not power the glow plugs if the engine coolant has an elevated temperature (greater than 50° C). To clear the DTC, a scan tool can be used to perform a forced glow service procedure. Do not replace the GPCM because the DTCs do not clear after replacing a glow plug. Using a scan tool, it can be seen that the resistance values of the glow plugs will not be reset in the GPCM — and the DTCs will not clear — without a glow cycle on the current engine start. To perform a forced glow using a scan tool: 1. Perform the necessary repairs 2. Connect a scan tool 3. Turn on ignition 0 and ignition 1 4. Command glow via device control for 1-2 seconds 5. Clear DTCs 6. Disconnect the scan tool 7. Turn off ignition 0 and ignition 1 for 30 seconds 8. Start the vehicle and verify DTCs are not present The voltage that is applied to the glow plugs during device control is very low at 4 volts. In addition, the GPCM has a maximum glow plug ON time of three minutes. The glow plugs cannot be turned on for a time period longer than three minutes.
SIDI Fuel Line Service - December 2010 GM Ecotec 4-cylinder engine family (2007-2010 RPO LNF, 2009-2011 RPO LDK, 2010-2011 RPO LAF, and 2011 RPO LHU) and GM High Feature V6 engine family (2008-2011 RPO LLT, 2010-2011 RPO LF1, and 2011 RPO LFW), with a Spark Ignited Direct Injection (SIDI) fuel system When servicing a fuel line on a Spark Ignited Direct Injection (SIDI) fuel system on the Ecotec 4-cylinder engine family and High Feature V6 engine family, the fuel pipe must always be replaced when it incorporates a tube nut fitting. If a tube nut fitting is loosened for a fuel system repair, the line must be replaced because, after the tube nut is torqued the first time, the sealing surface on the ball end of the pipe becomes modified in a way that will not seal properly again. The ball end of the pipe is a softer material than the mating surface and, once pressure is applied from torquing the tube nut, it deforms to form a good seal. It can be determined that a fuel pipe has been previously installed by viewing the ball end of the pipe. After the tubenut fitting has been torqued once and re-installed, the sealing surface of the ball end will show dual sealing bands, indicating that the pipe has been previously installed. If a pipe has been removed only once, it will only show one sealing band. Because of the deformation that takes place on the first tightening, the material may not seal properly the second time, which is why the fuel pipe must be replaced. New fuel pipes are ready to use right out of the package. A blue or transparent dry lube may be noticed on the ball ends of the pipe. Do not wipe off this lube. It aids in achieving proper torque and sealing at the ball end fitting of the pipe. Any time the fuel system is serviced, be sure to properly inspect, clean and torque the fuel pipe mating surfaces. Also, some fuel pipes have specific torque sequences that must be followed to ensure a good seal.
Squeak Noise on Brake Apply - November 2010 2004-2007 Buick Rainer; 2008 Buick Enclave; 2004-2010 Chevrolet Colorado, Chevrolet TrailBlazer models, GMC Canyon, GMC Envoy models; 2005-2009 Saab 9-7X; 2007-2008 GMC Acadia, Saturn OUTLOOK; 2008-2009 Chevrolet Malibu, Saturn AURA, Pontiac G6 A squeak noise may be heard when the brake pedal is slowly applied with the engine on or off. It also may occur when the brake pedal is released. The noise may be isolated to the master cylinder area. To correct this condition, remove as much of the old brake fluid from the master cylinder as possible and refill with new DOT 3 brake fluid, P/N 88862806. Start the vehicle and fully cycle the brake pedal until the noise diminishes to allow the new fluid to enter the system.
Various Electrical Conditions - October 2010 2005-2008 Cobalt, 2007-2008 G5 The following electrical issues may be evident on some models: SIR warning lamp illuminated, instrument panel lights flicker/inoperative, parking lamps flicker/inoperative, tail lamps dim/inoperative, trunk open lamp illuminated, radio inoperative, door lock inoperative, no start, or no crank. One possible cause of these conditions may be the interior wiring at the S361/J361 splice. Inspect splice S361/J361, parking lamp circuit, located in the body harness under the driver's seat. Remove the driver's seat from the vehicle and the driver's door opening carpet retainer. Peel back the carpet to about the "B" pillar and inspect the wires. If there is any damage, repair splice S361/J361 and other wires. Be sure to shrink-wrap any repairs to protect against moisture. If there is excessive moisture or water evident, water-test the vehicle for any leaks.
UBEC Fuses - September 2010 2006-2010 Impala and 2006-2007 Monte Carlo When diagnosing a condition with the turn signals, trunk actuator, courtesy lamps, or Brake Transmission Shift Interlock (BTSI), it may be possible to overlook some fuses in the Underhood Bussed Electrical Center (UBEC). The common architecture Body Control Module (BCM) uses several fuses for power, and the labeling of the fuses may be misread. • If the fuse in the UBEC labeled RTT/SIG is open, it will cause the right rear turn signal, the trunk actuator, and the BTSI to be inoperative. The right front turn signal will still function. • If the fuse in the UBEC labeled INT LIGHTS is open, it will cause the right front turn signal to be inoperative. The right rear turn signal will still function and the courtesy lamps will still function. • If the fuse in the UBEC labeled INT LTS/PNL DIM is open, the courtesy lamps will be inoperative. The instrument panel cluster backlighting will still function.
Power Steering Hose Retrofit Procedure - August 2010 2006 Impala or Monte Carlo or 2005-2006 Grand Prix, with a V8 engine When replacing the power steering hose, it's important to note that the new power steering hose is physically different than the original. The newly designed hose has a fin-type cooler built onto the hose assembly. The new design power steering hose should include installation instructions, which describe how to install the new design hose on vehicles that did not have this style hose previously. Per the installation instructions, it is necessary to drill mounting holes in the cradle to attach the new design hose assembly to the vehicle. Refer to GM bulletin #06-02-32-014 for more information.
Inoperative, Intermittent or Noisy A/C - July 2010 Some owners of GM vehicles may comment that their A/C is inoperative, operates intermittently or is noisy. No DTCs are set. After further investigation and diagnosis, it may be determined necessary to replace the Thermal Expansion Valve (TXV). However, before replacing TXVs, always follow the A/C Performance Diagnostic in the Service Information to verify the valve performance and review the diagnostic tips. The TXV meters the amount of liquid refrigerant that can flow into the evaporator. Located at the evaporator inlet, the TXV is the dividing point between the high and the low pressure sides of the A/C system. As the refrigerant passes through the TXV, the refrigerant pressure is lowered. Due to the pressure differential, the liquid refrigerant will begin to boil at the TXV outlet before entering the evaporator core. This characteristic is observed as a drop in temperature between the TXV inlet tube and the evaporator inlet tube. TVX FAILURE MODES Possible causes of inoperative or intermittent A/C: • Bulb Sensor: Temperatures on inlet and outlet tubes – Are the temperatures on both sides (inlet and outlet tubes) of the evaporator thermal expansion valve tube at the expansion device similar? If yes, replace the damaged or faulty thermal expansion valve. Pressures – Are both the low side and high side pressures within the specified values? Refer to the appropriate HVAC zone diagnostic. • Incorrect refrigerant charge – Diagnose and repair potential leak and/or fill A/C system with correct charge. • Leaking interfaces (Incorrect fastening at TXV or seal damage) – Apply correct torque or replace seals if necessary. • System contamination – Is the liquid line extremely cold at the expansion device location and warm beyond the expansion device location? The expansion device is restricted. Inspect for contamination (brown, powdery residue or metal flake) and replace TXV.
Allison Transmission Shift Conditions - June 2010 The 2001-2007 Silverado Classic, Sierra Classic; 2007-2010 Silverado, Sierra; and 2003-2010 Kodiak and Topkick, equipped with the Allison LCT1000 transmission (RPO M74, MW7) may have a delayed engagement or no engagement into Drive, a delayed engagement or no engagement into Reverse, or a range inhibit with several possible DTCs. These conditions may be more pronounced in cold climates during a cold start. When TC P0701, P0751, P0756, P0761, P0843, P0848, P0873, P0877 or P0894 set, it could indicate no or excessively low pump pressure as a result of a no prime or loss of prime condition within the transmission pump. Follow the diagnostic steps outlined in the Service Information. All of these DTCs, excluding P0894 could be set due to a fluid service/filter change, transmission service involving removing the pan, low fluid level caused by a leak, or long periods of storage. Also check the transmission fluid level using the Hot Check Procedure. Low fluid level may cause any of the listed DTCs to set, particularly during a cold ambient and cold vehicle start. In cold climates, ensure the fluid level is at the top of the HOT band. After checking the fluid level using the Hot Check Procedure, if any of the DTCs reset during a cold start, inspect the internal suction filter for possible cracks. Replacing the TCM will not likely correct any of the listed DTCs or low main line pressure.
Brake Pedal Kickback 1997-2007 Ford E-Series; 1999-2008 Ford F-Super Duty; 2000-2005 Ford Excursion Some vehicles equipped with the Hydro-Boost brake booster system may exhibit a brake pedal kickback and/or grabbing condition when applying the brakes that may be caused by contamination within the power steering system. Filter the power steering fluid by installing a temporary filter in the power steering system in line with the power steering hose. The filter needs to go in the low pressure line that goes from gear to cooler to reservoir, where it would be most accessible. After the filtering procedure is completed, if the brake pedal kickback persists, it may be necessary to replace the Hydro-Boost brake booster. - from ACDelco US TechConnect Newsletter
Squeak Noise from Rear of Vehicle - May 2010 1999-2007 Chevrolet Silverado (Classic), GMC Sierra (Classic); 2007- 2009 Chevrolet Colorado, Chevrolet Silverado, GMC Canyon, GMC Sierra, HUMMER H3, HUMMER H3T A squeak noise may be coming from the rear of the vehicle. During normal operation, certain vehicles may exhibit a squeaking noise that may be traced to the rear leaf springs. While this noise is an operating characteristic of leaf springs, the roads that the vehicle is driven on will affect the frequency and severity of this noise. This condition may be due to debris getting between the leaf springs. It has been found that the application of grease to the rear leaf springs will correct this condition and do a better job of preventing the noise from reoccurring than replacement of the springs. Apply a liberal amount of grease under the front and rear tip inserts for the #2 and #3 leaves, on top of the tip inserts, and in between the #1 and #2, and #2 and #3 leaves. Periodic cleanings and grease re-application may be necessary throughout the life of the vehicle. If this procedure does not correct the noise on 1500 Series (1/2 ton) models built prior to October 2004, the noise may be caused by an incorrectly dimensioned splay clip (the band holding the ends of the leafs together) that interferes with the leaf springs. A 5 mm (0.197 in) wider splay clip was introduced early in the 2005 model year to provide additional clearance. To correct this condition, it may be necessary to replace the rear leaf spring assembly. There was no change to the part number. For more information, refer to GM bulletin # 06-03-09-004B. - from ACDelco US TechConnect Newsletter
Fluid Flushing Requirements - April 2010 2005-2010 Chrysler, Dodge and Jeep Vehicles Chrysler Group vehicle fluid systems do not require regular flushing. These systems include: engine oil, transmission oil, axle lube, brake fluid, power steering fluid, and refrigerant. The only exception to this requirement are those fluid changes that are published in the vehicle maintenance schedules, e.g. engine coolant, and in instances where a failure has occurred and/or the system has become compromised, contaminated or overheated beyond the normal operating range. Aftermarket chemicals to flush the engine, transmission, brake or steering systems are not recommended. Chemicals contained in these products can damage the system elastomeric components, and contaminate the component fluid, leading to loss of system/ component durability and service life. When necessary, only the original approved system fluid should be used to flush these components using approved equipment. If the engine coolant contains a considerable amount of sediment, clean and flush the system followed by a thorough rinsing to remove all deposits and chemicals. Refill with a minimum of a 50% mixture of the specified coolant and distilled water. Refer to Chrysler bulletin #26-001-09 for more information. - from ACDelco US TechConnect Newsletter
2000-2010 OnStar-equipped Vehicles with Digital Hardware During battery parasitic drain testing, it is important to understand the power cycles of the various OnStar systems in order to avoid confusion about normal power consumption readings. All OnStar customers with currently active vehicles have digital/analog cellular capability. A green status LED on the OnStar keypad normally indicates an active OnStar account. A red LED indicates a system DTC. On Gen 6 and later systems, a clear or “dark” LED may indicate the OnStar system has been deactivated or may possibly have a no power concern/no communication. The OnStar system will stay powered up after the ignition is off for an extended time in order to allow for remote services like door unlock, horn chirp, light flash, etc., to take place as requested by the driver. Power cycle times vary depending on the generation of the OnStar system, and may be powered up continuously from 48 hours to 120 hours after the ignition is off. Technicians may identify the system generation by using a scan tool or by using www.onstarenrollment.com. The expected current draw of the OnStar module is: IGN ON - 240 to 400 mA IGN OFF - 3 to 20 mA for 48 hours IGN OFF - after 48 hours (120 hours on specified VCPs) - 0.2 to 0.8 mA - from ACDelco US TechConnect Newsletter
Engine Mount Replacement - March 2010 2004-2007 Cadillac CTS with 3.6L (LY7) or 2.8L (LP1) engine When replacing the engine mounts for any reason, follow these steps to prepare and install the new mount. The new part does not include the exhaust heat shield which must be re-used. Follow the appropriate Engine Mount Replacement procedure in SI to remove the old mount from the vehicle. Once the mount is removed, mark the hole location of the alignment pin on the mount heat shield. Using a suitable tool, remove the retaining spring nut from the top of the mount heat shield and discard the old mount. Prepare the replacement mount by cutting the lower locating pin off using a die grinder and cutting wheel. Align the marked hole on the heat shield with the top alignment pin on the replacement mount. Follow the appropriate Engine Mount Replacement procedure in the Service Information to install the new mount with heat shield into the vehicle. Verify that the heat shield is properly located on the mount. A retaining spring nut is not required. - from ACDelco US TechConnect Newsletter
Ignition Lock Cylinder - March 2010 2008-2009 Cadillac CTS (built prior to VIN breakpoint 90163371), 2005-2009 Chevrolet Cobalt (built prior to April 14, 2009), 2006-2009 Chevrolet HHR and Pontiac Solstice (built prior to April 14, 2009), 2007-2009 Chevrolet Equinox (built prior to July 2008), 2007-2009 Pontiac G5 (built prior to April 14, 2009) and Pontiac Torrent (built prior to July 2008), 2006-2009 Saturn SKY (built prior to April 24, 2009) — with an automatic transmission only Technicians may experience some difficulty installing the new style ignition lock cylinder on these models. Before installing the new cylinder, carefully inspect the housing for debris or damage from the old lock cylinder. No tools are required for installing the new lock cylinder. When installing into the housing, ensure that the lock cylinder is fully seated to ensure it latches into position. Do not use the old style lock cylinder that is still used on a manual transmission- equipped vehicle on a vehicle with an automatic transmission; the original binding condition will likely return. - from ACDelco US TechConnect Newsletter
Steering Wheel Vibration - Feb 2010 1996-98 Ford Crown Victoria, Mercury Grand Marquis, Lincoln Town Car A vibration or buzzing noise may be heard or felt in the steering wheel on right turns at engine RPMs between 590-1100. This condition may be caused by valve resonance and power steering pump pulsations. Replace the power steering pressure hose to dampen the noise. A new power steering hose bracket is attached to a stud on the engine, between the crankshaft pulley and power steering - from ACDelco US TechConnect Newsletter
Slipping Clutch Conditions - Feb 2010 2004-09 GM passenger cars or lightduty trucks equipped with a gasoline engine and manual transmission The Service Engine Soon (SES) light may illuminate and, using a scan tool, DTC P0502 (Vehicle Speed Sensor Circuit Low Voltage) may be found stored in the PCM. If no cause for the DTC can be found after following the appropriate Service Information diagnostics, the condition may be customer induced. Supporting data may be found in the freeze frame information stored with the DTC. Review the scan tool data parameters: Calculated Engine Load, Engine Speed, Output Shaft Speed Sensor and Clutch Pedal Position. Inform the customer that excessive slipping of the clutch with the vehicle stationary or moving at low speeds may cause this DTC to set. This is considered normal vehicle operation. - from ACDelco US TechConnect Newsletter
No Power Steering Assist - Feb 2010 Dodge Ram 2500 When replacing the power steering pump, properly torque the mounting bolts to specification during pump installation. Do not use an air ratchet. This is a vane type power steering pump with the mounting bolts going through the housing. If the bolts are over-torqued, they may compress the front and rear cover against the vanes, leading to severe wear, metal debris in the system, and eventual pump failure. - from ACDelco US TechConnect Newsletter
Manual Transmission Blocked Shift or Difficulty Shifting - January 2010 2003-2007 Saturn ION, 2004-2007 Saturn VUE, 2005-2010 Chevrolet Cobalt, 2005-2009 Pontiac G5, and 2006-2010 Chevrolet HHR — equipped with a Getrag manual transmission (RPO M86 or MG3) The manual transmission may exhibit a hop-out or blocked shift of 1st, 3rd and 5th gears or difficulty shifting. The shift lever roll pin may back out and contact the shift cover during a shift event, which can cause an incomplete, blocked shift or difficulty shifting the transmission. Prior to any internal transmission repairs, inspect the shift cover and lever to determine if the roll pin has backed out and is dragging on or contacting the housing. If roll pin contact is evident, then the shifting difficulty may not be an internal transmission condition. If the shift cover shows witness marks from contact with the roll pin, replace the complete shift cover assembly. Do not replace the transmission for this condition. If the roll pin is not dislodged, follow the appropriate Service Information diagnostics.
- from ACDelco US TechConnect Newsletter
Driveline Noises in 4WD - January 2010 2009 and prior Chevrolet and GMC light-duty trucks and SUVs equipped with 4WD, 2009 and prior HUMMER H2 and H3 These vehicles may exhibit a groan, growl, or moan noise when operating in 4WD Lock. The noise may be due to a vibration that is heard or felt as a result of the front axle being excited to resonance at its natural frequency. This is a combination of the transfer case chain link frequency, engine firing frequency, tire circumference variation, and various other tolerances built into the 4WD system. A groan, growl or moan noise on deceleration while in 4WD Lock is also the result of loading the transfer case chain, which is an operating characteristic. This is just one example of a transfer case link frequency as noted previously. On certain models, such as 3/4 –and 1-ton vehicles, tire pressures can vary from front to rear based on the manufacturer's specifications. Refer to the vehicle’s Tire Information Label for tire pressure specifications. The difference in tire pressures affects the rolling tire circumference from front to rear, which can increase driveline noise while in 4WD. For test purposes on vehicles with different tire pressures, drop the tire pressure in the rear to match the front. If the noise is reduced or eliminated, this confirms the difference in tire pressures from front to rear can affect the noise when operated in 4WD. Set the rear tire pressure back to the manufacturer's specification. No repairs are recommended for this condition. - from ACDelco US TechConnect Newsletter
Blower Motor Slows When Using Navigation Voice Control - December 2009 2004 Acura TSX with the navigation system In models with the navigation system, owners may comment that the fan speed drops when the navigation voice control switch is pressed. This is a normal operation that was added to the system during the 2004 model year. The blower motor fan speed drops to its lowest setting (1) as soon as the steering wheel-mounted voice control switch is pressed and released. This feature keeps air from the center vent from blowing onto the microphone in the ceiling and reducing the voice recognition capability. Owners of TSX models built before the VIN cutoff will receive this feature if the updated disc is purchased from the Acura website. - from ACDelco US TechConnect Newsletter
Battery Charging Precautions - December 2009 1995-2007 Mazda B-Series;1997-2003 Mazda Protégé; 1997-2005 Mazda Miata; 1997-2002 Mazda 626; 1997-2002 Mazda Millenia; 1997-2006 Mazda MPV; 2001-2006 Mazda Tribute; 2003-2007 Mazda6; 2004-2007 Mazda3; 2004-2007 Mazda RX-8; 2006-2007 Mazda5; 2006-2007 Mazda MX-5; 2007 Mazda CX-7
The maximum voltage for vehicle electrical components is approximately 15 volts. Battery chargers generate at least 15 volts, and in some cases, as much as 20 volts under the high charge setting. - from ACDelco US TechConnect Newsletter
Brake Pad Cracks - December 2009
- from ACDelco US TechConnect Newsletter
Service Charging System Message on DIC - November 2009
- from ACDelco US TechConnect Newsletter
- from ACDelco US TechConnect Newsletter
Grunt Noise While Turning - October 2009 1999-2001 Ford Windstar Some vehicles equipped with a 3.8L engine may exhibit a "grunt" noise -- a low, loud, rumbling hydraulic noise and shudder -- while turning the steering wheel. This may be caused by the original design power steering hose or by air trapped in the power steering system after hose replacement. Replace the power steering pressure hose with service hose YF2Z-3A719-AA to correct the noise. This service hose includes a pulse suppressor that requires all air to be removed during fluid fill of the system. Refer to the appropriate Service Information for removal and installation details. Replacing the power steering pump or gear will not result in correction of the grunt noise. The service hose is intended to correct the grunt noise only. Do not use this service hose to repair any other power steering condition. Any air left in the system will result in continuation of the grunt noise as well as other noises. Refer to the power steering system fill procedure in the appropriate Service Information. It may take several times of performing the evacuation procedure to remove all of the air from the system. Be sure to pull over 68 kpa (20 in/hg) on the gauge with the engine running while evacuating the system. One way to check for air in the system after the evacuation process is to mark the fluid level on the power steering reservoir prior to starting the engine. If the fluid level drops when the engine is started, there is still air in the system. Repeat the bleed process until there is no fluid level drop evident in the reservoir. An additional way to check for air in the system is to install the vacuum pump on the reservoir, start the engine, but do not turn the steering wheel, then slowly pull vacuum to between 68-85 kpa (20-25 in/hg). If there is still air in the system the pump will moan before reaching 68 kpa (20 in/hg). If this moaning is heard, repeat the bleed procedure until reaching 68-86 kpa (20-25 in/hg) with no moan noise. - from ACDelco US TechConnect Newsletter
"No Cap" Fuel Filler System - October 2009 Ford vehicles with the Easy Fuel™ fuel filler system The Easy Fuel "no cap" fuel filler system eliminates the need for a fuel filler cap. The spring loaded fuel door is held closed by two latches that can only be released by a standard size unleaded fuel nozzle, or the special plastic funnel included with the vehicle. A flexible rubber seal, attached to the outer fuel filler door, seals the fuel filler. If the seal becomes damaged, it must be replaced to prevent possible contamination of the fuel tank. In the event fuel needs to be added from a portable fuel container, it's necessary to use the white plastic funnel included with the vehicle. It is the same diameter as an unleaded fuel nozzle. Fully insert the funnel into the fuel filler neck to add fuel from a portable container. Do not insert the nozzle of a portable fuel container or aftermarket funnel. - from ACDelco US TechConnect Newsletter
Audio System Noise When using Portable Playback Devices - October 2009 2010 and prior GM passenger cars and trucks, including Saturn; 2010 and prior HUMMER H2, H3; 2005-2009 Saab 9-7X Some portable audio equipment may be susceptible to certain types of electronic noise present in the vehicle's 12V power outlet. Here are two ways to eliminate this type of interference: - If the audio device is capable of being self-powered (battery), use it that way instead of plugging it into the vehicle's power outlet. - Have the customer purchase a Ground Loop Isolator. This device plugs in between the radio and the audio device. - from ACDelco US TechConnect Newsletter
The Role of the Automatic Tensioner - September 2009 Belt Performance Directly Affects Other Components - September 2009 Belt Inspection Changes - August 2009 Neoprene vs. EPDM Construction - August 2009 1997/02 Ford Expedition, 1999 Lincoln Navigator
Improper Use of Conductance Testing on New Batteries A new battery does not develop its full performance capabilities until it has been through several discharge/charge cycles. This means a new battery may not be capable of producing its optimum current and cold cranking amps (CCA). If a new battery that has not gone through a cycling period is tested using a conductance-type battery tester, the resulting CCA may be lower than indicated on the battery's rating label. This could lead to condemning an otherwise good battery. Conductance is a measurement of a battery's current producing capability. Conductance testers can accurately identify batteries that have reduced performance after being in service, but should never be used to determine the state of health, state of charge or CCA rating of a new, never installed battery. Also, conductance testing of new batteries should never be used to determine the warrantable condition. To check the condition of a battery prior to installation to be sure there is adequate voltage to start the vehicle, measure open circuit voltage (OCV) using a digital voltmeter (DVOM). An OCV of 12.24V is adequate to provide the power requirements for starting most vehicles under most conditions. The battery should be in service for several days before performing a conductance test.
Battery Testing Procedures Follow these tips when using a conductance tester to ensure accurate test results. Using non-approved adapters or improper test procedures can lead to failing test results for batteries that are not defective. Be sure the battery in the tester is good or you may get inaccurate results. To check the conductance tester, be sure OCV on the tester matches the OCV measured with a known-good DVOM (may vary slightly due to different internal resistance). Be sure to get good connections between the battery terminals and the tester clamps. Each tester clamp has two jaws. Each jaw is wired to a different part of the tester, and it is essential that both jaws make good contact. If the connections to the battery terminals in the vehicle are in doubt or the tester displays REPLACE BATTERY or BAD CELL - REPLACE, disconnect the battery being tested from the vehicle. Retest the battery with both of the vehicle's battery cables disconnected from the battery. When using an adapter, be sure the adapter makes good contact with the lead terminal surface on the battery. Never use steel bolts, nuts, washers, etc., when testing a side terminal battery. Only use the adaptors included with the conductance tester. The coating on other adapters may affect the tester's accuracy. Battery Warranty ACDelco batteries are covered by a comprehensive warranty program. Any independent service center can accept an ACDelco battery that is under warranty and not functioning properly from a customer for return, even if the battery was purchased from another retailer or service center. ACDelco will warrant the battery, and in the process, the service center may earn some additional service business and customer loyalty. - from ACDelco US TechConnect Newsletter
Remote Keyless Entry Inoperative 1995-1998 Saab 900, 1999-2002 Saab 9-3 Sedan, 2003 Saab 9-3 Convertible, and 1999-2008 Saab 9-5 The Remote Keyless Entry (RKE)/ central locking may be intermittently inoperative or the radio may not turn off when removing the key. This concern may be difficult to duplicate and no DTCs are set. If the B+ (plunger) switch in the ignition switch sticks in/on when removing the ignition key, these conditions will be present. When B+ voltage is present, it supplies fuse 5 in panel 22a. This fuse supplies DICE and TWICE a key-in ignition signal, disabling RKE. This condition is often caused by liquids or debris entering into the lock cylinder, causing the cylinder not to fully release upon key removal. The center portion of the cylinder should pop up when the key is removed. To repair this condition, carefully remove the immobilizer antenna (if equipped) from around the ignition switch to check for evidence of spilled liquids. If residue is found, remove the ignition lock cylinder and inspect the cylinder and switch for binding. It may be possible to clean the key cylinder by soaking it in warm, soapy water; then blow it out with compressed air. Lube the lock cylinder with light machine oil before re-installing. If the cylinder still binds, it should be replaced. If residue is found in the switch, it must be replaced. The key cylinders can be ordered keyed to the vehicle. The antenna for the RKE is mounted in the center console by the rear ashtray. - from ACDelco US TechConnect Newsletter
Air Cleaner Cover Installation 2004-09 Cadillac SRX, 2005-09 Cadillac STS (except V Series), and 2004-07 Cadillac CTS (except V Series) If replacing only the air filter element, the air cleaner (outlet side) cover does NOT need to be completely removed from the housing. The cover will pivot to allow for removal and installation of the filter element. The air cleaner (outlet side) cover can be difficult to reinstall in the proper position if it has been fully removed from the housing. The tabs (Fig. 14, A) must be correctly aligned with the hinge slots (Fig. 14, B) in the (inlet side) housing. It is possible to incorrectly reassemble the cover to the housing without the cover seated properly at the hinge. When viewed from the top, there may not be a visual indication that the box is not properly sealed. To reduce the risk of an improperly sealed air cleaner assembly and dirty air entering the engine, verify that the cover is seated correctly in the housing before reinstalling the cover bolts. To check that the cover is properly seated once the cover bolts have been torqued down, gently pull up on the cover/MAF Sensor adapter. This gives a positive indication that the tabs of the cover are seated in the hinge slots. - from ACDelco US TechConnect Newsletter - June 2009
A/C Compressor Service Tips ACDelco studies have shown replacement air conditioning compressors fail four times more often than original compressors because of a failure to properly restore the system. ACDelco has disassembled, reviewed, and analyzed hundreds of air conditioning compressors returned under warranty. The failure of these compressors can be grouped into three major categories: • Lubrication • Refrigerant • Debris When repairing A/C conditions, performing the necessary service to protect replaced parts is important to avoid replacement failures and comebacks. Prior to and after compressor failure, debris particles from a failure flow throughout the refrigerant system in both directions. These particles imbed themselves in various internal components and cannot be completely flushed from the system. The most cost-effective service method for protecting the compressor and other new components is to install a suction screen ahead of the compressor and an in-line filter ahead of the control valves. These protection devices have virtually no effect on overall A/C system performance but they greatly improve the protection of a compressor from any residual failure debris. A quick visual inspection may prevent needless compressor replacement caused by other conditions, such as a low charge, Diagnostic Trouble Codes (DTC), electrical connections, or loose fasteners. Check for proper charge levels and purity as well as confirmation of clutch engagement. Compressors with a low charge make noise. A proper charge may silence a noisy compressor. - from ACDelco US TechConnect Newsletter - May 2009
Checking Coolant Hoses What is the best way to check the condition of the coolant hoses on an engine? If you answered X-ray vision, you're right. That would allow you to see inside the hose to view the tiny cracks on the inside walls of the hose where damage begins. The second best, and more realistic way, to check any coolant hose is with the squeeze test. The squeeze test can be used to inspect any coolant hose for the negative effects of Electro Chemical Degradation (ECD), which is the primary culprit of coolant hose failure. ECD creates fine cracks, or striations, in the tube wall inside the hose. The fine cracks extend from the inside to the outside of the hose tube near one or both ends of the hose and weaken the structure of the tube.
Regular Maintenance Evidence of ECD depends on the quality of the hose, time and vehicle use, so there is no readily identifiable maintenance interval to follow. The squeeze test of coolant hoses should be included as part of a vehicle's regular maintenance. To perform a squeeze test, squeeze the hose near the clamps or connection using the following procedures: • Make sure the engine is cool • Use your finger and thumb, not your whole hand, to check for softness • Squeeze near the connections. ECD occurs within two inches of the ends of the hose, not in the middle. • If the ends feel soft or mushy but the middle feels firm, the hose is under attack from ECD - from ACDelco US TechConnect Newsletter - May 2009
Electro Chemical Degradation ECD is an electrochemical attack on the tube compound. Different metals found in an engine system release an ionic discharge, generating 5 to 150 millivolts. The coolant contacts the various metals, picks up the charge and discharges the electrical energy into the hose. The voltage discharge initiates an electrochemical process that ultimately creates small cracks or striations (markings with parallel grooves) in the hose tube. Over time, these cracks widen, resulting in pinhole leaks and, eventually, leading to catastrophic failure. Heat does not cause the failure, but it does accelerate the electro chemical degradation process. Inferior hoses are more susceptible to ECD. It is recommended to change these hoses every four years or sooner if used in a fleet application. Some standard hoses have revealed damage and failures as early as 20,000 miles in fleet applications. To beat the effects of ECD, a new innovative tube material has been developed that is Electro Chemically Resistant (ECR). In testing, the ECR hose has been shown to last 200,000 miles. In addition to ECD damage, during a routine inspection of coolant hoses, always check for any heat damage, oil damage, and abrasive ozone damage (caused by pollution attacking bonds in rubber components that appears as tiny cracks at curves and bends) of the hoses. - from ACDelco US TechConnect Newsletter - May 2009
Wheel Spacers Original equipment (OEM) wheels and GM accessory wheels are designed to mount directly to the vehicle's wheel hubs without need for spacers (adapters). Some aftermarket wheels are manufactured to fit a limited number of wheel hub diameters and rely on spacers to accommodate the differences. In some instances, owners have installed aftermarket wheels that require the use of spacers and later switched back to the OEM wheels. If the spacer is not removed from the wheel hub, it will interfere with the proper fit of the OEM wheel. The spacer can affect wheel nut torque, causing loosening and possible wheel detachment. Other effects include wobbling, vibration and unnatural tire wear. If a vehicle displays such characteristics, and has previously been fitted with aftermarket wheels, check for wheel hub spacers and remove them if they are present. - from ACDelco US TechConnect Newsletter - May 2009
Discharged Battery, Slow Starting 1997-1998 Buick Skylark; 1997-1998 Chevrolet Cavalier and Malibu; 1997-1998 Oldsmobile Achieva and Cutlass; 1997-1998 Pontiac Grand Am and Sunfire -- with 2.2L, 2.4L, 3.1L engines (RPOs LN2, LD9, L82) The battery may be weak or discharged, the starting motor may turn slowly, the generator may not be charging. Check for a loose generator output and battery positive cable terminal at the starting motor. This may cause a high resistance in the battery positive circuit from the generator to the battery. Also inspect the condition of the starting motor B+ stud, wire, ring terminals and nut. If these conditions are found, the generator and battery should not be damaged and will not require replacement. - from ACDelco US TechConnect Newsletter - May 2009
Starter Motor Continues to Run or Crank 1995 Buick Riveria; 1995 Cadillac Eldorado, Eldorado Touring Coupe, Seville; 1995 Chevrolet Camaro; 1995 Oldsmobile Aurora; 1995 Pontiac Firebird -- with 3800, 4.0L, 4.6L, 5.7L engines (RPOs L47, L36, LT1, LD8, L67, L37); 1994-95 Chevrolet and GMC Truck C/K, G, P models -- with 5.7L, 7.4L engines (RPOs L05, L19) The starter motor may continue to run or crank after the vehicle is started or turned off. The starter motor solenoid will not disengage because of a ground to the #6 circuit. With the #6 circuit ground to a resistive ground, current is fed back through the windings to the ground, holding in the plunger and causing the starter to continue to run. Disconnect the #6 circuit lead at the starter "S" terminal. With the ignition Off or in Run, use an Ohm meter to check for any electrical path between the ring terminal on the #6 circuit lead and ground. If found, eliminate the grounding condition. Reroute any wires as necessary. - from ACDelco US TechConnect Newsletter - May 2009 |
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