ADR Indicator: Operation

WARNING: This page is about a different car, the 2006 Dodge Sprinter. However, it is still accessible from the selected car via links, so may be relevant.

The constant engine speed (ADR) indicator gives an indication to the vehicle operator concerning the operating status of the constant engine speed (ADR) feature. The ADR 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 Engine Control Module (ECM) over the Controller Area Network (CAN) data bus. The ADR 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 indicator for the following reasons:

Constant Engine Speed (ADR) Indicator Lamp-On Message - Each time the cluster receives an ADR indicator lamp-on message from the ECM, the indicator will be illuminated. The indicator is illuminated when the ADR feature has been activated with the ADR switch, and is turned off when the ADR feature is deactivated with the ADR switch. The ADR indicator will be extinguished if the ADR feature is turned off because the park brake has been released or the vehicle is in motion. The ADR indicator will also be extinguished if the service brake pedal is depressed, but the ADR feature will automatically be restored and the indicator illuminated when the brake pedal is released. The indicator remains illuminated until the cluster receives a lamp-off message from the ECM, or until the ignition switch is turned to the Off position, whichever occurs first.

The ECM continually monitors the constant engine speed (ADR) switch and electronic messages from the Controller Antilock Brake (CAB) concerning the status of the four wheel speed sensors, the park brake switch and the brake lamp switch to determine the correct operating mode for the ADR feature. The ECM then sends the proper lamp-on or lamp-off messages to the instrument cluster. See the owner's manual in the vehicle glove box for more information on the features, use, activation and deactivation of the constant engine speed (ADR) feature. For proper diagnosis of the ADR feature, the ECM, the CAB, the CAN data bus, or the electronic message inputs to the instrument cluster that control the ADR indicator, a diagnostic scan tool is required. Refer to BODY DIAGNOSTIC PROCEDURES .