
162 RENR9348-01
Troubleshooting Section
Test Step 7. Check the Injector Harness
Under the Valve Cover for a n Open
Circuit or a Short Circuit
Electrical shock hazard. The electronic unit injec-
tor system uses 90-120 volts.
A. Remove the electrical power from the ECM.
B. Remove the valve cover in order to gain access
to the suspect injector.
C. Disconnect the harness connector from the
suspect injector.
g01147088
Illustrat
ion 9 3
Connector terminals for the injector so lenoid
D. Thoroughly clean the terminals on the injector
solenoid and on the harness connector.
E. Use a jumper wire to short circuit the connector
terminals for the suspect injector. This will
effectiv
ely replace the injector solenoid with a
short circuit.
F. Restore t
he electrical power to the ECM.
G. Perform the “Injector Solenoid Test” at least two
times.
Note: The injector solenoid that shares the supply
wire of th
e injector that is short circuited may indicate
a false test result. Disregard this test result.
H. Remove th
e electrical power from the ECM.
I. Remove the jumper wire from the injector
connecto
r. This will effectively replace the injector
solenoid with an open circuit.
J. Restore
the electrical power to the ECM.
K. Perform the “Injector Solenoid Test” at least two
times.
L. Remove the electrical power from the ECM.
Expected Result:
Cat ET display
s “Short” for the cylinder with the
jumper wire and “Open” when the jumper wire is
removed.
Results:
•
OK – Cat ET disp
lays the correct status during
the test.
Repair: The ha
rness wiring is OK. There may be a
problemwiththeinjector.Useamultimetertocheck
the resistance of the suspect injector solenoid.
The correct resistance of each injector solenoid is
1.06 ± 0.05 Ohms at 25 °C (77 °F).
If the resistance of the solenoid is not within
specifications replace the faulty injector. Verify that
the problem
is resolved.
If the resistance of the solenoid is within
specificati
ons the problem may be intermittent. If
the problem is intermittent, refer to the diagnostic
functional test Troubleshooting, “Inspecting
Electrical
Connectors”.
STOP.
•
Not OK – Cat ET did not display the correct status
during the test.
Repair: There is a problem with the injector
harness under the valve cover. There may be a
problem wi
th a connector. Repair the wiring and/or
the connector, when possible. Replace parts, if
necessary.
STOP.
Test Step 8
. Check the E CM for Proper
Operatio
n
Electrical shock hazard. The electronic unit injec-
tor system uses 90-120 volts.
A. Remove the electrical power from the ECM.
B. Fabricate a jumper that is long enough to reach
from the P2 ECM connector to the engine ground
stud. Crimp a connector socket to one end of the
jumper wire.