Pinpoint Test BM: The SELECTABLE Drive Mode Or Trail Control Feature Is Inoperative, Cannot Be Enabled Or Disabled And Abs Module Communication Concern With ATCM

Normal Operation and Fault Conditions 

The selectable drive mode switch is part of the ATCM. When the drive mode switch is activated, the ATCM sends a message to the ABS module over the FD-CAN. If the ABS module does not receive any messages within a certain time frame (usually less than 1 second) or if the message contains invalid information, the ABS module sets a DTC. For information on the all messages sent to the ABS module by the ATCM, REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description .

The trail control switch is used to activate and deactivate the trail control feature. The switch is an internal component of the ATCM. When the driver presses the trail control switch, the ATCM sends a trail control switch message to the ABS module over the FD-CAN. 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. 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 Fault Trigger Conditions 

Possible Sources 

• Network communication concern
• ATCM