Porsche 928 Workshop Manual page 589

Electronic Fuel lniection
Fault, Fault Code
Possible Causes, Elimination, Remarks
If the idle speed contact values are not obtained in this test.
repeat it directly at the throttle valve switch:
disconnect the plug from the throttle valve switch. Connect an
ohmmeter between terminals 1 and 2 of the throttle valve swftch,
using test leads.
Display:
Throttle valve closed < 10 Q
n
Throttle valve opening angle > 1' = m 51
c3
#==ia=:
Idle speed contact
(Q)
Open circuit
Fault code l-15
Test procedure same as for short to ground.
(From 1991 models on, fault is memorized.)
Check that setting is correct and adjust if necessary.
Cause may be incorrectly set throttle valve switch or accelerator
cable, for example.
lJ24-12
LH-Diagnosis/Troubleshooting
Printed in Germany - Xxv, ,sw