Porsche 928 Workshop Manual page 596

928 54
928 GT
Electronic Fuel Injection
24
Fault, Fault Code Possible Causes, Elimination, Remarks
Test point 10
Injection circuit
shut down
Fault code l-31
Test point 11
Defective control unit
Fault code l-41
The CO content must go up.
Important: Continue this test only until a change is noted
in the CO content at the CO tester.
If the control unit does not process the ground signal, check its
coding (see testing plan page D24/28-8) before replacing it.
The ignition circuit monitoring relay is mounted on the retaining plate
for the LH and EZK control units.
If an ignition circuit fails, the power supply to the injector valves is in-
terrupted.
At the same time one of the two colored LEDs integrated into the
relay lights up.
Injection circuit I shut down - red LED lights up.
Injection circuit I shut down - green LED lights up.
Fo troubleshooting, see 928 Repair Manual volume I-A. pages 28-77
Renew control unit
LH-Diagnosis/Troubleshooting
Printed In Germany - XXV, 1990
D24-19