Symptom Related Diagnostic Procedures

Checking the cruise control function

Fault-tracing information
If there is no cruise control function it may be because:
- The criteria for activation of cruise control have not been met
- The switch for RTI and audio/carphone is defective
- The driver is driving with the brake pedal slightly pressed
- Defective steering wheel module (SWM).
For the cruise control to activate, the following conditions must be met:
- The switch is in the ON position
- Speed exceeds 35 km/h
- The brake and clutch pedal are released
- The park/neutral position (PNP) switch is unaffected (automatic cars)
- Certain diagnostic trouble codes (DTCs) can affect the function of the cruise control
- The cruise control sends an activation request and control to the engine control module (ECM) via the steering wheel module (SWM). The steering wheel module (SWM) sends the request on to the engine control module (ECM) via the controller area network (CAN).

Note! The engine control module (ECM) disengages the cruise control if the speed falls below 75% of the set speed. This could happen on a steep incline for example, where the engine is unable to maintain a constant speed.

Continue - steering wheel module (SWM)

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Checking the component and wiring, steering wheel module (SWM)

- Ignition on
Click on the VCT2000 symbol.
Read off the status of the buttons in the cruise control switch. Check that the status changes between Off and On when the relevant button is pressed in.
If the function is correct, there is communication between the cruise control and steering wheel module (SWM).

Does the status of the cruise control change when the button is pressed?

Yes - engine control module (ECM)

No - Checking the contact reel

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Checking the contact reel

- Ignition off
- Disconnect the contact reel from the steering wheel module (SWM)
Measure the resistance between:
- terminals #B1 and #B2
- terminals #B1 and #B3
- terminals #B2 and #B3.
The resistance must be infinite.
Check the cable between:
- terminal #B1 and contact reel terminal #1
- terminal #B2 and contact reel terminal #2
- terminal #B3 and contact reel terminal #3.
Check for an open-circuit.

Other information:
- To replace the contact reel, see Contact reel / steering wheel angle sensor, replacing Contact Reel / Steering Wheel Angle Sensor, Replacing
- To connect the breakout box, see Connecting the breakout box
- For information about signals, see Signal specification
- Checking wiring and terminals Checking Wiring And Terminals.

Was a fault detected?

Yes - Fault Found

No - Car equipment

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Car equipment

Is the car equipped with RTI?

Yes - Checking components and wiring

No - Checking components and wiring

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Checking components and wiring

- Ignition off
- Disconnect the RTI switch
- Ignition on.
Activate and read off the status of the buttons in the audio/carphone switch.
If the readings give a correct result, the fault is in the RTI switch.

Other information:
- To access the RTI switch, see the relevant service procedure.

Was the audio/carphone switch status OK?

Yes - Fault Found

No - Checking components and wiring

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Checking components and wiring

- Ignition off
- Disconnect the audio/carphone switch by disconnecting the lower connector on the switch
- Ignition on.
Activate the buttons. Read off the status of the buttons in the cruise control switch.
If the readings give a correct result, the fault is in the audio/carphone switch.

Other information:
- To access the audio / carphone switch, see the relevant service procedure.

- Ignition off
- Disconnect the audio/carphone wiring by disconnecting the lower connector on the cruise control switch
- Ignition on.
Activate the buttons. Read off the status of the buttons in the cruise control switch.
If the readings give a correct result, the fault is in the wiring between the audio/carphone switch and the cruise control switch.

Other information:
- To access the cruise control switch, see the relevant service procedure.

Was the status of the cruise control switch OK?

Yes - Fault Found

No - Checking components and wiring

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Checking components and wiring
- Check the voltage between terminals #B1 and #B3. The voltage must be approximately 12 V
- Check the voltage between terminals #B2 and #B3. The voltage must be approximately 5 V
- Check the voltage between terminal #B3 and the battery negative terminal. Voltage must be approximately 0 V.
If the readings are OK, the fault is in the cruise control switch.

Other information:
- To connect the breakout box, see Connecting the breakout box .

Was a fault detected?

Yes - Fault Found

No - No Fault Found

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Checking components and wiring, engine control module (ECM)

- Ignition on
Click on the VCT2000 symbol
Read off the status of the buttons in the cruise control switch. Check that the status changes between Off and On when the relevant button is pressed in.
If the function is correct, there is communication between the cruise control and engine control module (ECM).

Does the status of the cruise control change when the button is pressed?

Yes - No Fault Found

No - Checking the status of the pedal position sensor

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Checking the status of the pedal position sensor
A number conditions must be met for cruise control to be allowed by the engine control module (ECM). Some of these conditions are speed related, the clutch and the brake pedal must not be depressed and certain diagnostic trouble codes (DTCs) must not be stored etc. The clutch and brake pedal position sensors are checked to determine if they are in a position where the engine control module (ECM) allows cruise control.

Note! On cars with automatic transmissions, the parameter for the brake pedal position sensor displays "Active" (the brake pedal position sensor allows the cruise control to function).

- Ignition on
- Click on the VCT2000 symbol
- Check if the clutch pedal position sensor and the brake pedal position sensor are in the "Active" position when the pedals are in the unaffected positions. Check that the status changes when the pedals are depressed. The brake pedal and the clutch pedal must be in the "Active" position for the engine control module (ECM) to allow cruise control

Continue - DONE

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