Symptom Related Diagnostic Procedures
Checking speed related power steering
A fault in the speed related power steering can result in the steering becoming abnormally stiff at low speed or abnormally light at high speed.
Fault causes could be:
- No power supply to the speed related power steering control module
- Open-circuit or loose connection in the wiring between the control module and the central electronic module (CEM)
- Open-circuit or loose connection in the wiring between the control module and the solenoid on the steering gear
- Contact resistance and oxidation in the control module or solenoid connectors
- Defective control module for speed related power steering.
Continue - Checking the power supply
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Checking the power supply
- Ignition off
- Check the control module connector for speed related power steering. Check for contact resistance and oxidation. In particular, check for any damage
- Ignition on.
Measure the voltage between terminals #4 and #3 in the control module connector for speed related power steering. The voltage should be battery voltage.
Other information
- To access the control module for speed related power steering, see Control module steering gear, replacing Service and Repair.
Was the voltage correct?
Yes - Checking the signal cable
No - Checking the wiring
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Checking the wiring
- Ignition off.
Check the fuse for the control module for speed related power steering.
Check the cable between the fuse and control module terminal #4. Check for an open-circuit. Check for a short-circuit to ground.
Check the cable between the control module and ground terminal. Check for an open-circuit. Check for a short-circuit to supply voltage.
Also check the ground terminal. Check for contact resistance and oxidation.
Remedy as necessary.
Other information
- For further information about the fuses and ground terminal, see the Wiring Diagram
- Checking wiring and terminals Checking Wiring and Terminals.
Continue - Verification
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Checking the signal cable
- Ignition off.
Check the cable for the vehicle speed signal between the central electronic module (CEM) terminal #10D (#B10) and the control module for speed related power steering terminal #2. Check for an open-circuit. Check for a short-circuit to supply voltage. Check for a short-circuit to ground.
Remedy as necessary.
Other information
- To access the central electronic module (CEM) connector, see Central electronic module (CEM), replacing Service and Repair
- Connecting the breakout box Connecting the Breakout Box, Central Electronic Module (CEM)
- For information about signals, see Signal specification Signal Specification
- Checking wiring and terminals Checking Wiring and Terminals.
Was a fault detected?
Yes - Verification
No - Checking signal cables
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Checking signal cables
Check the connector for the solenoid on the steering gear. Check for contact resistance and oxidation.
Check for damage carefully.
Check the signal cable between the control module for speed related power steering terminal #5 and the solenoid connector terminal #1. Check for an open-circuit. Check for a short-circuit to supply voltage. Check for a short-circuit to ground.
Check the signal cable between the control module for speed related power steering and the solenoid connector terminal #2. Check for an open-circuit. Check for a short-circuit to supply voltage. Check for a short-circuit to ground.
Remedy as necessary.
Other information
- To access the solenoid connector, see Steering gear, replacing Steering Gear, Replacing
- Checking wiring and terminals Checking Wiring and Terminals.
Was a fault detected?
Yes - Verification
No - Replacing component
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Replacing component
Replace the control module for speed related power steering.
Other information
- To replace the control module for speed related power steering, see Control module steering gear, replacing Service and Repair.
Continue - Verification
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Verification
Verification
Hint: After carrying out the repair, check that the fault has been remedied.
- Ignition off
- Reinstall the connectors, components etc.
- Engine running.
Change the vehicle speed signal from the central electronic module (CEM) by clicking on the VCT2000 symbol.
Switch between 0 km/h and 110 km/h and test at the same time, by turning the steering wheel, that the servo assistance for the steering changes in relation to the speed.
Does the servo assistance change in relation to the speed?
Yes - Troubleshooting procedure complete
No - Fault-tracing information
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Fault-tracing information
Information
Fault-tracing information
The fault should have been detected and remedied. As this is not the case fault-tracing has failed.
Exit fault-tracing for this diagnostic trouble code (DTC) or make another attempt.
Do you want to exit fault-tracing?
Yes - Exit Fault-tracing
No - Attempt New Test
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Attempt New Test - Checking the power supply
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