Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Normal Operation and Fault Conditions
The trail control switch is used to activate and deactivate the trail control feature. When the driver presses the trail control switch, the IPC receives a ground signal from the switch and illuminates the trail control indicator. The IPC sends a trail control switch message to the GWM over the HS-CAN 3 and the GWM relays this message to the ABS module over the HS-CAN 2. The ABS module adjusts the operating parameters of the anti-lock and stability control features, and aids in maintaining the set speed of the vehicle. Vehicle speed is adjusted using the cruise control steering wheel switches.
The driver door ajar switch is hard-wired to the ABS module for trail control feature safety operation. When the trail control feature is enabled and active, and the driver door is opened, the IPC notifies the occupants through the message center and the driving torque propelling the vehicle is disabled. If descending an incline, the ABS maintains the descent speed until the vehicle is no longer on an incline. If ascending an incline, the vehicle rolls backward at a speed of 3 km/h (2 mph) until it is no longer on an incline.
| DTC | Description | Fault Trigger Conditions |
|---|---|---|
| P166B:11 | Drivers Door Status Correlation: Short to Ground | This DTC sets when the hard-wired driver door ajar switch circuit is shorted to ground. |
| P166B:12 | Drivers Door Status Correlation: Short to Battery | This DTC sets when the hard-wired driver door ajar switch circuit is shorted to voltage. |
| P166B:64 | Drivers Door Status Correlation: Signal Plausibility Failure | The ABS module also receives a driver door ajar message from the BCM and compares the hard-wired door ajar input to the message. If the hard-wired switch state does not match the message and DTC P166B:11 or P166B:12 is not set, then this DTC sets. |
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.