ASR/ESP Indicator - Operation

OPERATION

The Acceleration Slip Regulation (ASR) (also known as traction control)/Electronic Stability Program (ESP) warning indicator gives an indication to the vehicle operator of the current status of the ASR system, the ESP system or both in providing road control and stability to the vehicle. This indicator is controlled by a transistor on the instrument cluster circuit board based upon cluster programming and electronic messages received by the cluster over the Controller Area Network (CAN) data bus from the Controller Antilock Brake (CAB) (also known as the Antilock Brake System/ABS or Electronic Stability Program/ESP controller).

The ASR/ESP warning 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 ASR/ESP warning indicator for the following reasons:

- Bulb Test - Each time the ignition switch is turned to the ON position the ASR/ESP warning indicator is illuminated briefly as a bulb test.
- ASR/ESP Warning Indicator Lamp-On Message - Each time the cluster receives an electronic ASR/ESP warning indicator lamp-ON message from the CAB, the indicator will be illuminated. This indicator can be flashed ON and OFF, or illuminated solid, as dictated by the CAB message. The indicator is illuminated solid when the ASR system has been manually deactivated using the ASR switch. The indicator is flashed ON and OFF when the ASR system, the ESP system, or both are actively engaged in providing the vehicle with electronic traction or stability enhancements. The indicator remains illuminated solid or flashing 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 all of the ASR system and ESP system circuits and components to determine the correct operation for these systems. The CAB then sends the proper lamp-ON or lamp-OFF messages to the ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN or KOMBI). See the owner's information packet in the vehicle glove box for more information on the features, use, and recommendations concerning activation and deactivation of the ASR system.

For proper diagnosis of the ASR switch, the ASR system, the ESP system, the CAB, the EMIC, the CAN data bus or the electronic communication related to ASR/ESP warning indicator operation, a diagnostic scan tool is required. Refer to the appropriate diagnostic information.