Symptom Related Diagnostic Procedures

Cruise control fails to operate
1. Check whether the wiring harness coupling at the control module (N4/2) is pushed all the way on.
2. Test cruise control with adapter.

Sporadic cruise control failure
Poor electrical contact at control module (N4/2) due to loose plug-socket connections.
Bend the sockets together, ensure that terminal assignments at coupling remain correct.

Cruise control fluctuates by 5 to 7 km/h, regardless of vehicle speed

Note: This complaint is especially obvious when the pushbutton switch is used to increase vehicle speed. When the pushbutton switch is released, the vehicle continues to accelerate by approx. 5 to 7 km/h. Then the speed falls again, after which it increases, etc.

Control module (N4/2) defective.
Check wiring harness for short-circuits. If in order, replace actuator (M16) and then control module (N4/2).

Vehicle jerks throughout entire speed range
1. Check throttle control for ease of movement and wear.
2. Check to ensure that the correct control module (N4/2) and the appropriate cruise control (CC) reference resistor (R29) for the vehicle model are installed.
3. Check wiring to actuator (M16) and control module (N4/2) for correct terminal assignments at the connectors. (Refer to wiring diagram.) Electrical Diagrams
4. Check to ensure that good contact is present in the wiring harness at the connector for the rear wheel-speed signal (X62/13), if necessary clean or tighten connector.
5. Replace actuator (M16).

Actuator (M16) rattles at key position "II"
1. Check connections on actuator (M16) and control module (N4/2) to ensure good contact; if necessary; press in sockets.
2. Replace actuator (M16).