Diagnostic/Test Plan For Actuators (Drive Link)

Re: Warning lamps and information lamp
The respective warning or information lamp (as selected) does not flash.

- Check bulb.

- Check wiring to Central Information System and control unit according to wiring diagram.

Re: Pump relay

Return pump does not operate.

- Carry out troubleshooting procedure according to test point 24 (Fault code 40). Test 24/Fault Code 40

MV (solenoids) front and rear

Solenoids or return pump do/does not operate correctly. If a mechanical fault is present in a solenoid, the fault will not be stored in the fault memory.

Hydraulic pipes or electrical wiring may have been interchanged accidentally.

If a fault has been stored in the fault memory, start by remedying this fault.

Test step 1 (not o.k.):

- Inlet solenoid faulty.

- Electrical wiring/hydraulic piping interchanged.

Test step 2 (not o.k.):

- Brake pedal has not been operated.

- If another wheel locks up (with parking brake released and selector lever of Tiptronic vehicles in N position), the hydraulic pipes or electrical wires have been interchanged.

Test step 3 (not o.k.)

- Exhaust (outlet) solenoid faulty.

Solenoids (MV) for ABD

ABD solenoids not o.k. (Operation or sealing).

Note: A correct check of the ABD solenoids is only possible if no faults are present at any ABS inlet solenoid or ABS exhaust (outlet) solenoid Always start by reading out the fault memory and remedy this fault first as required.

Test step 1 not o.k.

- Operation of switchover valve not o.k.

- Return pump operation not o.k. Check pump operation, selecting the pump relay on the Drive links menu (Pump should then start to run).

Test step 2 not o.k.

- Operation of intake valve not o.k.

Test step 3 not o.k.

- Poor bleeding of ABD secondary circuit.

- Intake or switchover valve leaky.