Porsche 928 Workshop Manual page 606

028 s4
028 GT
Fuel system, electronic control
24
Check-Engine Lamp
(Malfunction Indicator Light M.1.L)
As from model year '91, Californian legislation prescribes a warning lamp which lights up if a part rele-
vant to the exhaust gas fails.
As a function check of the warning lamp, k lights up when the ignition is switched on and goes out
once the engine is running when this is started without depressing the accelerator.
The warning lamp has a flashing code to indicate a defective fault path.
To trigger off the flashing code, fully depress the accelerator pedal with the engine off and the lgni-
tion on for 3 seconds until the Malfunction Indicator Lamp flashes. Then remove foot from accelerator.
If no fault is recorded, i.e. no warning came from the indicator light, there appears the flashing code
1
0 = Lampon 0 = Lampoff
1500
no fault.
If the warning light did indicate a warning, i.e. there is a fault, there appears a flashing code, e.g.
1124
Constant fault (2 with loose contact)
DME/LH control unit
1124
Oxygen sensor
1 1 2 4
The flashing code is listed in the Diagnosingfrroubleshooting plan on page D 24/28-7.
The fault can also be read direct using System Tester 9288. After a repair the fault memory must be
erased using the System Tester.
a
LH-Diagnosing/Troubleshooting
Printed In Germany - XXV, 1990
D 24128 - 29