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8.ECM
Reconnect the disconnected ECM harness connectors.
While monitoring scan tool, connect a jumper wire between the (K181)
signal circuit of the sensor connector and the (K915) return circuit of the
sensor connector.
Does the DTC P0192 set?
Ye s>>
Refer to the INTERMITTENT CONDITION Symptom (Diag-
nostic Procedure). (Refer to 9 - ENGINE - DIAGNOSIS
AND TESTING)
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
No>>
Replace the ECM.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
Page 538 of 5267
P0201-INJECTOR #1 CONTROL CIRCUIT
For a complete wiring diagramRefer to Section 8W.
Page 539 of 5267

When Monitored:
While the engine is running.
Set Condition:
When the injector current falls below a calibrated threshold.
Possible Causes
PASS TROUGH CONNECTORS OPEN
FUEL INJECTOR
INJECTOR HARNESS OPEN
HIGH SIDE DRIVER HARNESS OPEN
LOW SIDE DRIVER HARNESS OPEN
ECM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.OTHER DTC’S
With the scan tool, read DTCs.
Are all 6 of the injector DTC’s (P0201 - P0206) present?
Ye s>>
Go To 2
No>>
Go To 3
2.PASS TROUGH CONNECTORS OPEN
Inspect wiring harness for signs of multiple open circuits between the ECMand the injector pass through connec-
tors. Inspect the wiring harness between the pass through connectors to theinjectors.
Are there open circuits in the wiring harness?
Ye s>>
Repair or replace the open connectors or wiring.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 3
3.FUEL INJECTOR
Turn the ignition off.
Disconnect the pigtail nuts from the suspect injector. Using an Ohmmeter,measure the resistance between the sole-
noid posts of the injector.
NOTE: Be sure to zero the ohm meter prior to checking the injector circuit.
Is the resistance less than 1 ohm and greater than 0 ohms?
Ye s>>
Go To 4
No>>
Replace the fuel injector.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
Page 540 of 5267

4.INJECTOR HARNESS OPEN
Connect the pigtail nuts for the suspect injector.
Disconnect the injector harness connector for the suspect injector.
Measure the resistance of the injector harness circuit between the high
side driver circuit and the low side driver circuit for the suspect injector
at the injector harness connector.
NOTE: Be sure to zero the ohm meter prior to checking the injec-
tor circuit.
Is the resistance less than 1 ohm and greater than 0 ohms?
Ye s>>
Go To 5
No>>
Replace or repair the injector harness.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
5.HIGH SIDE DRIVER HARNESS OPEN
Disconnect the ECM harness connectors.
Disconnect the Injector harness connector.
Check connectors - Clean/repair as necessary.
Measure the resistance of the Bank 1 high side driver circuit between
the ECM connector and the injector harness connector.
Is the resistance less than 10 Ohms?
Ye s>>
Go To 6
No>>
Replace or repair the open engine harness.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
Page 541 of 5267
6.LOW SIDE DRIVER HARNESS OPEN
Measure the resistance of the Bank 1 low side driver circuit between
the ECM connector and the injector harness connector.
Is the resistance less than 10 Ohms?
Ye s>>
Te s t C o m p l e t e .
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
No>>
Replace or repair the open engine harness.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
Page 542 of 5267
P0202-INJECTOR #2 CONTROL CIRCUIT
For a complete wiring diagramRefer to Section 8W.
Page 543 of 5267

When Monitored:
While the engine is running.
Set Condition:
When the injector current falls below a calibrated threshold.
Possible Causes
PASS TROUGH CONNECTORS OPEN
FUEL INJECTOR
INJECTOR HARNESS OPEN
HIGH SIDE DRIVER HARNESS OPEN
LOW SIDE DRIVER HARNESS OPEN
ECM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.OTHER DTC’S
With the scan tool, read DTCs.
Are all 6 of the injector DTC’s (P0201 - P0206) present?
Ye s>>
Go To 2
No>>
Go To 3
2.PASS TROUGH CONNECTORS OPEN
Inspect wiring harness for signs of multiple open circuits between the ECMand the injector pass through connec-
tors. Inspect the wiring harness between the pass through connectors to theinjectors.
Are there open circuits in the wiring harness?
Ye s>>
Repair or replace the open connectors or wiring.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 3
3.FUEL INJECTOR
Turn the ignition off.
Disconnect the pigtail nuts from the suspect injector. Using an Ohmmeter,measure the resistance between the sole-
noid posts of the injector.
NOTE: Be sure to zero the ohm meter prior to checking the injector circuit.
Is the resistance less than 1 ohm and greater than 0 ohms?
Ye s>>
Go To 4
No>>
Replace the fuel injector.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
Page 544 of 5267

4.INJECTOR HARNESS OPEN
Connect the pigtail nuts for the suspect injector.
Disconnect the injector harness connector for the suspect injector.
Measure the resistance of the injector harness circuit between the high side driver circuit and the low side driver
circuit for the suspect injector at the injector harness connector.
NOTE: Be sure to zero the ohm meter prior to checking the injector circuit.
Is the resistance less than 1 ohm and greater than 0 ohms?
Ye s>>
Go To 5
No>>
Replace or repair the injector harness.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
5.HIGH SIDE DRIVER HARNESS OPEN
Disconnect the ECM harness connectors.
Disconnect the Injector harness connector.
Check connectors - Clean/repair as necessary.
Measure the resistance of the Bank 1 high side driver circuit between
the ECM connector and the injector harness connector.
Is the resistance less than 10 Ohms?
Ye s>>
Go To 6
No>>
Replace or repair the open engine harness.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)