Porsche 928 Workshop Manual page 1278

39
Differential, transaxle system 929
Fault, DTC Possible causes, remedy, notes
Test
point
11
Fmnt right
ABS valve
DTC 32
Test
point
12
Rear axle
ABS valve
DTC 33
4. Check whether
the valve relay is energized (voltage is present at the
solenoid valves).
To make this check, connect all plugs and the relay. Push back the
protective tube on the transverse lock valve plug (in the wheel hous-
ing at the rear leff).
Switch the ignition off, then on again.
Battery voltage must be present at the black wire.
If no voltage is present: continue with DTC 34 (valve relay). Comply
with the testing notes.
If voltage is present, try replacing the PSDIABS control unit (output
stage defective).
Testing notes
If a voltage supply plug to the solenoid valves (ABS valves or diffe-
rential 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 re-
conneded until the ignition has been switched off and on again.
Comply with note under test point 10: Front lefl ABS valve (DTC 31).
When troubleshooting, proceed as for DTC 31, but use PIN 22 instead
of PIN 19 on the control unit plug.
To check the internal resistance of the ABS valve (atler pulling off the
12-pin plug at the hydraulic unit), measure between PIN 3 and PIN 4
(instead of PIN 1 and PIN 4).
a
Comply with note under test point 10: Front lefl ABS valve (DTC 31).
0
For troubleshooting, proceed as for DTC 31, but use PIN 2 instead of
PIN 19 of the control unit plug.
To check the internal resistance of the ABS valve (afier pulling off the
12-pin plug at the hydraulic unit), measure between PIN 5 and PIN 4
(instead of PIN 1 and PIN 4).
D39 - 240
a
PSD diagnosis/Troubleshooting
Printed in Germany -XXXV, ,666