341503 - D72 THE CRUISE CONTROL SYSTEM + CONTROL IS NOT WORKING

The Cruise Control system does not increase the speed when the ring nut is turned to "+".

For safety reasons the Cruise Control is inhibited above a maximum speed and below a minimum speed. If these speeds are exceeded the Cruise Control no longer works.

STEP	OPERATIONS TO BE CARRIED OUT	TEST RESULTS
1	CHECK USING DIAGNOSTIC EQUIPMENT	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Connect the diagnostic test equipment (Examiner or other instruments) to the tester input.Check for the presence of faults in the engine management control unit	Move on to Step	1. Error detected in the control unit	1. Continue following the instructions for the diagnostic equipment
			2. No communication with the control unit	2. Restore the connection between the engine management control unit and the diagnostic connector (Wiring Diagram ) E5060 CRUISE CONTROL
2	CRUISE CONTROL SELECTOR CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check that the Cruise Control contacts are working properly in the "+" position    Continue following the instructions in the test 5580AB Cruise Control SET + control check	Move on to Step	No continuity	Replace the steering column switch unit lever with the Cruise Control incorporated    See in Op. 5580A10 Cruise control LEVER ASSEMBLY - R.R.
3	SUPPLY CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	With the ignition key in the ON position and the Cruise Control in the ON and "+" position, check that there is a voltage signal from the Cruise Control to the engine management control unit (Wiring Diagram ) E5060 CRUISE CONTROL	Move on to Step	No voltage detected	Repair the connections (Wiring Diagram ) E5060 CRUISE CONTROL
4	CHECK ON CORRECT OPERATION	ALL OK	PROBLEMS ENCOUNTERED	ACTION
2.4 20 V,2.0 TB,3.0 V6	Check that the fault is no longer present		Fault persists control unit defective	Replace the engine management control unit    See in Op. 1056B82 Injection/ignition system CONTROL UNIT (one) - R.R.
4	CHECK ON CORRECT OPERATION	ALL OK	PROBLEMS ENCOUNTERED	ACTION
2.4 JTD 10V	Check that the fault is no longer present		Fault persists control unit defective	Replace the engine management control unit    See in Op. 1060G80 Diesel electronic injection system CONTROL UNIT - R.R.