Porsche 928 Workshop Manual page 597

24
Electronic Fuel Injection
928 S4
928 GT
Fault, Fault Code
Test point 12
No power supply
to LH control unit (V)
a) Permanent positive
SUPPlY (S +)
Possible Causes, Elimination, Remarks
Connect voltmeter to
terminals
17
and 4 of LH
control unit plug with a test
lead.
Display: battery voltage
Checking current path
according to wiring
diagram.
b) Power supply through
LH relay XXV
At the LH control unit,
connect a voltmeter to
terminals 17 and 9, and run
to terminal 21 (ground on
body) using test leads. The
LH relay must be energized
Display: battery voltage
No display:
Check relay Relais XXV and
current path according to
wiring diagram.
D 24 - 20
LH-Diagnosisflroubleshooting
a
Printed In Germany - Xxv, ,990