Porsche 928 Workshop Manual page 257

928
Differential, transaxle system
39
Fault, DTC Possible causes, remedy, notes
1. Switch off the ignition and pull the plug off the control unit. Check
PIN 19 of plug to PIN 17 and to PIN 23 for continuity.
If necessary, interrupt the circuit (plug at hydraulic unit) and localize
the discontinuity by reference to the wiring diagram.
2. Pull off the valve relay (7-pole) at the hydraulic untt.
Check for a short circuit to plus or to ground in the circuit as de-
scribed in point 1 by measuring at PIN 19.
If a fault is detected, interrupt the circuit
as
described in point 1 in or-
der to localize the incorrect short-circuit to plus or to minus.
3. Check resistance between PIN 19 of the plug and terminal 30 at the
valve relay.
lf nominal value is obtained: proceed with point 4.
If nominal value is not obtained:
Pull off the 12-pole plug at the hydraulic unit.
Check internal resistance of the AES solenoid valve. Measure
between PIN 1 and PIN 4 (at the hydraulic unit).
Nominal value 0.7...1.7 0.
If nominal value is incorrect: replace the hydraulic unit.
PSD diagnosis/Troubleshooting
Printad in G-ny -XXXV, 1886
D39 - 239