Porsche 928 Workshop Manual page 1276

39
Differential, transaxle system 928
a
Fault, DTC Possible causes, remedy, notes
Test point 7
Front right
speed sensor
DTC 22
General procedure as for DTC 21 (test point 6)
1. Internal resistance / continuity between PIN 47 and PIN 46 at control
unit plug.
2. Speed sensor signal: If the ASS tester is used, turn the wheel
selector switch to the front right wheel.
Test point 8
Rear right
speed sensor
Rear left
Test point 9
Rear left
speed sensor
DTC 24
Test point
10
Front left
ABS valve
DTC 31
General procedure as for DTC 21 (test point 6)
1. Internal resistance/continuity between PIN 42 and PIN 43 at control
unit plug.
2. Speed sensor signal: If the ASS tester is used, turn the wheel
selector switch to the rear right wheel.
General procedure as for DTC 21 (test point 6)
1. Internal resistance / continuity between PIN 44 and PIN 45 at control
unit plug.
2. Speed sensor signal: If the ABS tester is used, turn the wheel
selector switch to the rear left wheel.
a
Certain faults in the ABS valve area (short circuit to plus or short circuit
to 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 stored as an
ABS valve fault
in the DTC memory of the control unit.
When the DTC memory is read out, it is possible in the above situation
for
two faults to be displayed (ABS valve and valve relay).
D39 - 230
PSD diagnosis/Troubleshooting
Printed in Germany - XXXV, 1995