ADR Indicator - Operation

OPERATION

The constant engine operating speed governor/working speed control (ADR) indicator gives an indication to the vehicle operator when the engine operating speed governor/working speed control feature has been activated. 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 Programmable Special Module (PSM) (also known as the Parameterizable Special Module/PSM).

The ADR indicator Light Emitting Diode (LED) or textual message display is completely controlled by the instrument cluster logic circuit, and that logic will only allow this indicator or textual message display to operate when the instrument cluster detects that the ignition switch is in the ON position. Therefore, the LED or the textual message will always be OFF when the ignition switch is in any position except ON. The LED only illuminates or the textual message is only displayed when it is activated by the instrument cluster logic. The instrument cluster will turn ON the ADR indicator or textual message display for the following reasons:

- ADR Indicator Lamp-On Message - On vehicles not equipped with the optional steering wheel buttons, each time the cluster receives an electronic ADR indicator lamp-ON message from the PSM indicating that the constant engine operating speed governor/working speed control is turned ON, the ADR indicator will be illuminated. The indicator remains illuminated until the cluster receives a lamp-OFF message from the PSM, or until the ignition switch is turned to the OFF position, whichever occurs first. On vehicles equipped with the optional steering wheel buttons, each time the cluster receives an electronic ADR indicator lamp-ON message from the PSM indicating that the constant engine operating speed governor/working speed control is turned ON, an Operating speed governor active textual message will appear within the cluster multi-function display. The textual message remains displayed until the cluster receives a lamp-OFF message from the PSM, or until the ignition switch is turned to the OFF position, whichever occurs first.

The PSM continually monitors the ADR switch and electronic messages from the Controller Antilock Brake (CAB) (also known as the Antilock Brake System/ABS or Electronic Stability Program/ESP controller) to determine the correct operating mode for the engine operating speed governor/working speed control. The PSM 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).

For proper diagnosis of the engine operating speed governor/working speed control (ADR) feature, the ADR switch, the PSM, the CAB, the CAN data bus or the electronic communication related to ADR indicator operation, a diagnostic scan tool is required. Refer to the appropriate diagnostic information.