Fault 10 / Fault Code 31

10: Front left ABS valve Fault code - 31 -

Possible Causes, Elimination. Remarks

Certain faults in the ABS valve area (short to positive side or to earth/ground) in a control wire) can also be shown as a valve relay fault by the 9288 system tester.

A fault in the ABS valve circuits is normally memorized as an ABS valve fault in the control unit fault memory.

When the fault memory is read out, it is possible in the above situation for 2 faults to be displayed (ABS valve and valve relay).




1. Switch off the ignition and pull the plug off the control unit. Check PIN 19 of plug against PIN 17 and against PIN 23 for continuity. If necessary, interrupt the circuit (plug at hydraulic unit) and localize the break by reference to the circuit diagram.

2. Pull off the valve relay (7 pole) at the hydraulic unit.
Check for a short to the positive side or to earth/ground in the circuit as described in Item 1, by measuring at PIN 19.

If a fault is detected, interrupt the circuit as described in Item 1, in order to localize the incorrect short-circuit to the positive side or to earth/ground.




3. Check resistance between PIN 19 of the plug and terminal 30 at the valve relay base.

Desired value approx. 1...2 ohm.

If desired value is obtained: proceed with Item 4.

If desired value is not obtained:



Pull off the 12-pole plug at the hydraulic unit (a Torx wrench is needed to relieve tension).

Check internal resistance of ABS solenoid valve. Measure between PIN 1 and PIN 4 (at the hydraulic unit).
Desired value 0.7...1.7 ohm.

If desired value is incorrect: renew the hydraulic unit.




4. Check whether the valve relay is energized (electric current present at solenoid valves).

To make this check, connect all plugs and the relay. Push back the protective cap on the locking valve block plug.

Switch the ignition off, then on again.

The voltage from the car's electrical system must be present at PIN 1 and PIN 2.

If no power supply is present: continue with fault code - 34 - (valve relay). Comply with testing notes.

It the power supply is present, renew the PDAS/ABS control unit experimentally (output stage defective).


Testing notes

If a power supply plug to the solenoid valves (ABS or differential lock) is pulled off while the ignition is switched on, the valve relay will be de-energized. It is not re-energized when the plug is reconnected until the ignition has been switched off and on again.