Porsche 928 Workshop Manual page 1272

39
Differential, transaxle system
928
l
Fault, DTC Possible causes, remedy, notes
Test point 4
Transverse lock,
deviation
DTC 14
During the transverse lock regulating phase, the monitoring circuit in
the PSD/ABS control unit has identified excessive variations be-
tween
the
nominal
and
actual values.
Possible faults
- Lock control circuit poorly bled (lock operation hydraulics)
- Lock hydraulics leaking
- Lock solenoid valve has a mechanical defect
- Lock cylinder does not retain preset pressure (leaking through re-
lief bore)
- Inadequate signal from
a
rear wheel speed sensor
- Fault in transverse lock plates
- Insufficient hydraulic pressure builds up at plates, e.g. because
thrust-bearing bolt of engaging lever is wrongly adjusted (enga-
ging lever makes contact).
Procedure
I. Check lock hydraulics for external leaks. Replace defective parts
if necessary.
2. Repeat bleeding procedure for lock control circuit (lock hydrau-
lics). If new parts have been installed, the lock must be bled as ap
propriate (Page D39-202d).
3. Check speed sensor signals
(Pages D39-236
. ..D39-238).
4. Measure thickness of plates with lock measuring cylinder (special
tool 9514). Page D39-202e.
5. Check pressure at locking torque (friction value of the lock)
(Pages D39-203...D39-213).
D39 - 234 PSD diagnosis/Troubleshooting
Printed in Gummy - XXXV, IS96