Porsche 928 Workshop Manual page 614

920 s4
928 GT
Fuel System / Electronic Control
28
Fault, Fault Code Possible Causes, Elimination, Remarks
Test point 3
Temperature sensor II 51
Fault code 2-14
Disconnect the EZK control unit plug
At the EZK control unit plug, connect terminals 19 and 18 with the
ohmmeter.
Test values at: 0°C = 4.4 - 6.8 kQ
15-30°C =
1.4 - 3.6 kQ
40°C = l-1.3 kn
80°C = 250 390 Q
100°C = 160 210 Q
If these values are not reached, test at the sensor in the thermostat
housing. However, do not connect both contact tabs with the
ohmmeter but test each plug contact at the temperature sensor sepa-
rately against ground (there are two independent temperature sen-
sors).
Test point 4
Idle or full load
contact
Fault code 2-15
Test point 5
Load signal
Fault code 2-21
To identify a ground short.
Test as stated in test point 1 or 2 (EZK test plan)
From LH control unit terminal 25 a lead runs to EZK control unit ter-
minal 9 and transmits a signal representing actual load.
If a fault occurs here, check the wiring and the plug contacts. If the
load signal is not present at the EZK control unit, the ignition is re-
tarded in the part-load operating range by up to 25" CS (full load
mapped zone, as protective circuit). Renew the control unit if neces-
sary.
Test point 6
Transmission protection
switch
(automatic transmission
only)
Fault code 2-26
To,protect the transmission shift elements, the ignition is retarded
during transmission shifts,
If a fault is indicated here, connect the voltmeter to the socket sleeve
side of terminals 1 and 2 at the 3-pin plug in the trunk well.
EZK-Diagnosis/Troubleshooting
Printed in Germany - XXV 1990
028-7