Traction Control Malfunction Indicator

A traction control (ASR) malfunction indicator is standard equipment on all instrument clusters. The traction control malfunction indicator is located near the lower edge of the instrument cluster, to the right of the multi-function indicator display. The traction control malfunction indicator consists of an icon that graphically depicts a tire and two skid marks imprinted within a rectangular cutout in the opaque layer of the instrument cluster overlay. The dark outer layer of the overlay prevents the indicator from being clearly visible when it is not illuminated. An amber Light Emitting Diode (LED) behind the cutout in the opaque layer of the overlay causes the icon to appear silhouetted against an amber field through the translucent outer layer of the overlay when the indicator is illuminated from behind by the LED, which is soldered onto the instrument cluster electronic circuit board. The traction control malfunction indicator is serviced as a unit with the instrument cluster.

The traction control (ASR) malfunction indicator gives the vehicle operator an indication when the traction control system is faulty or inoperative. This indicator is controlled by a transistor on the instrument cluster circuit board based upon cluster programming and electronic messages received by the cluster from the Controller Antilock Brake (CAB) over the Controller Area Network (CAN) data bus. The traction control malfunction indicator Light Emitting Diode (LED) is completely controlled by the instrument cluster logic circuit, and that logic will only allow this indicator to operate when the instrument cluster detects that the ignition switch is in the On position. Therefore, the LED will always be off when the ignition switch is in any position except On. The LED only illuminates when it is provided a path to ground by the instrument cluster transistor. The instrument cluster will turn on the traction control malfunction indicator for the following reasons:
- Bulb Test - Each time the ignition switch is turned to the On position the traction control indicator is illuminated as a bulb test until the engine is started.
- Traction Control (ASR) Malfunction Indicator Lamp-On Message - Each time the cluster receives a traction control malfunction indicator lamp-on message from the CAB, the indicator will be illuminated. The indicator remains illuminated until the cluster receives a lamp-off message from the CAB, or until the ignition switch is turned to the Off position, whichever occurs first.

The CAB continually monitors the traction control (ASR) system circuits and sensors to decide whether the system is in good operating condition. The CAB then sends the proper lamp-on or lamp-off messages to the instrument cluster. If the CAB sends a lamp-on message after the bulb test, it indicates that the CAB has detected a system malfunction and that the traction control (ASR) system has become inoperative. The CAB will store a Diagnostic Trouble Code (DTC) for any malfunction it detects. In addition, if the traction control malfunction indicator is illuminated, the CAB will deactivate an activated traction control system and engine power output may be reduced. See the owner's manual in the vehicle glove box for more information on the features, use, activation and deactivation of the traction control (ASR) system. For proper diagnosis of the traction control system, the CAB, the CAN data bus, or the electronic message inputs to the instrument cluster that control the traction control malfunction indicator, a DRBIII(R) scan tool is required. Refer to the appropriate diagnostic information.