KENR6933 177
Troubleshooting Section
Results:
•
OK – The harness connects the ECM to the glow
plug start aid relay and there are no shorts to other
circuits. The
ECM or the glow plug start aid relay is
suspect.ProceedtoTestStep4.
•
Not OK – The har
ness is faulty.
Repair: If the resistance between P1:57 and
each of the oth
er pins on the P1 connector is less
than 10,000 Ohms then there is a short circuit or
high resistance in the connection to another wire.
Locate the op
en circuit, the short circuit or high
resistance in the connection in the harness. Repair
the connectors or the harness and/or replace the
connectors o
r the harness. Ensure that all of the
seals are correctly in place and ensure that the
connectors are correctly coupled. Replace any
fuses that m
ay be open circuit.
Use the electronic service tool in order to clear all
logged dia
gnostic codes and then verify that the
repair has eliminated the fault.
If the faul
tstillexists,proceedtoTestStep4.
Test Step 4. Bypass the ECM In Order to
Check the Operation of the Glow Plug
Start Aid Relay
A. Turn the keyswitch to the OFF position.
B. Disconne
ct the connection from test point “D” on
the glow plug start aid relay.
C. Connect a
jumper wire between the battery ground
and terminal “D” on the glow plug start aid relay.
D. Measure t
he voltage from the battery ground and
terminal “B” on the glow plug start aid relay.
E. Connect a
multimeter between terminal “B” on the
glow plug start aid relay and the battery ground.
F. Turn the
keyswitch to the ON position.
Note: The engine has not been started at this Test
Step.
G. Use the electronic service tool in order to operate
the glow
plugs.
H. Measure the voltage from the battery ground and
termina
l“B”ontheglowplugstartaidrelay.
Expected Result:
The keyswitch is in the OFF position. The voltage
should be 0 Volts DC.
The keyswitch is in the ON position. The measured
voltage for the
12 Volt systems is a constant 10.5 to
13.5 Volts DC. The measured voltage for the 24 Volt
systems is a constant 21.0 to 27.0 Volts DC.
Results:
•
OK – The glow pl
ug start aid relay is operating
correctly. Reconnect the connection to test point
“D” on the glow plug start aid relay. Proceed to
Test Step 5.
•
Not OK – The glow plug start aid relay is faulty.
Repair: Replace the glow plug start aid relay.
Use the electronic service tool in order to clear all
logged diagn
ostic codes and then verify that the
repair eliminates the fault.
If the fault s
till exists, proceed to Test step 5.
Test Step 5. Check the ECM
A. Disconnect the P2 connector and disconnect the
P1 connector from the ECM.
B. Temporarily connect a test ECM. The test ECM
should be programmed with the same values and
parameters
as the suspect ECM.
C. Check the screw for the ECM connector for the
correct tor
que of 5.0 N·m (44 lb in).
D. Ensure that all connectors, pins and sockets are
correctly c
oupled and/or inserted.
E. Use the electronic service tool in order to perform
a“GlowPlu
g Override Test”.
Expected Result:
The replacement ECM functions correctly. Performing
the “Glow Plug Override Test” energizes the glow
plugs.
Results:
•
OK – The replacement ECM functions correctly.
Repair: In
stall the replacement ECM. Refer to
Troubleshooting, “Replacing the ECM”.
STOP.
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