Operation CHARM: Car repair manuals for everyone.

Faulty Signal






Faulty signal

Checking the function




Caution! Carry out the test with the vehicle raised so that all four wheels can rotate freely with the mounting at the ends of the control arms to prevent damage to the drive shafts.

Warning! Ensure that the vehicle is safely raised. Check that no objects are caught in the tire treads.

Note! If the vehicle is equipped with TRACS (traction control system) or Traction Control (DSTC (Dynamic stability and traction control), STC (Stability and traction control)) the function must be deactivated. This is carried out by removing the fuse for the brake system pump motor in the engine compartment relay and fusebox. Note that diagnostic trouble codes (DTCs) will be stored in the brake control module (BCM). These must be erased before returning the vehicle to the customer.

- Engine idling
- Read off the oil pressure.
Check that the function of the oil pressure sensor is OK. Run the engine with the vehicle on the lift to increase the clutch oil pressure. Read off the pressure during the test drive. Check that the pressure has been updated.

Hint: The oil pressure sensor has a measurement range of 0 to 4 Mpa.

Check the connector between the differential electronic module (DEM) and the oil pressure sensor. Check for contact resistance and oxidation.
Also check the clutch for leakage.
Remedy as necessary.

Other information:
- For further information about the fuses and relays, see the Wiring Diagram
- Signal specification, differential electronic module (DEM) , AW50/51 AWD
- Temperature / pressure sensor active on demand coupling, replacing, B5254T2, AW50/51 AWD
- Active on Demand Coupling (AOC), replacing
- Checking wiring and terminals Checking Wiring And Terminals





Continue - Verification

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Verification




Verification

Hint: After carrying out the repair, check that the fault has been remedied.








Caution! Carry out the test with the vehicle raised so that all four wheels can rotate freely with the mounting at the ends of the control arms to prevent damage to the drive shafts.

Warning! Ensure that the vehicle is safely raised. Check that no objects are caught in the tire treads.

Note! If the vehicle is equipped with TRACS (traction control system) or Traction Control (DSTC (Dynamic stability and traction control), STC (Stability and traction control)) the function must be deactivated. This is carried out by removing the fuse for the brake system pump motor in the engine compartment relay and fusebox. Note that diagnostic trouble codes (DTCs) will be stored in the brake control module (BCM). These must be erased before returning the vehicle to the customer.

- Ignition off
- Reinstall the connectors, components etc.
- Engine idling
- Read off the oil pressure.
Check that the function of the oil pressure sensor is OK. Run the engine with the vehicle on the lift to increase the clutch oil pressure. Read off the pressure during the test drive. Check that the pressure has been updated.

Hint: The oil pressure sensor has a measurement range of 0 to 4 Mpa.





Is the function OK?

Yes - Verification completed

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 function

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