Repair Procedure: Aftermarket device causing issues on full-size pickups

Some 2019 and 2020 Chevrolet Silverado and GMC Sierra vehicles may exhibit some of the following symptoms:
  • IPC warning lights or messages
  • Erratic IPC gauge
  • Cruise control may not set or not set at a certain speed
  • Issues with SPS programming or reprogramming a module
  • A lack of communication with various modules
  • Any of the following DTCs: U0073,U0100, U0101, U0102, U0121,U0128, U0131, U0140, U0415, U0422, U2413 and/or P0700

The cause of these concerns may be an aftermarket device that is plugged inline with the BCM X1 connector (shown at the bottom of the page). These aftermarket devices are typically used to change the speed calibration when a different-sized wheel/tire is installed. The devices are neither supported nor recommended by GM and will void the vehicle's warranty.

Before beginning any in-depth repairs, inspect the vehicle for such a device.

Note that, if the vehicle is modified with a lift kit, lowering kit, different-sized wheels/tires or similar alteration, it is a good indication that one of these devices is installed.

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