Driver Assistance Systems Disabled due to Incorrect Tire Size

The Lane Keep Assist and Forward Collison Alert systems may become inoperative on some 2020-2022 Encore GX and 2021-2022 Trailblazer models. While driving, the Lane Keep Assist and vehicle detection icons may flash and a System Unavailable message may be displayed when the Lane Keep Assist button on the center console is pressed. (Fig. 20)


Fig. 20


If a tire has been replaced with a tire size that is different than the original equipment manufacturer (OEM) tire size, the wheel speed discrepancy while traveling on a straight road will cause all driver assistance systems (B174W Frontview Camera Module) that rely on wheel speed sensor data inputs to be disabled. These system include:

  • Lane Keep Assist (LKA)
  • Lane Departure Warning (LDW)
  • Forward Collision Alert (FCA)
  • Low Speed Collision Mitigation Braking (LSCMB) (RPO UHY)
  • Pedestrian Collision Mitigation Braking (PCMB) (RPO UKJ)


If these conditions are found, inspect the tires on the vehicle to ensure that they are all the same size as the original OEM tires. (Fig. 21)


Fig. 21


If a tire has been replaced that is not the correct OEM size, it will have to be replaced with the correct OEM size tire as indicated on the vehicle tire placard, located below the driver’s door latch. This is not a warrantable repair.


– Thanks to Chris Hightower

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