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7.ECM
Reconnect the ECM harness connector.
Turn the ignition on.
With the scan tool, erase DTCs.
While monitoring with scan tool, use a jumper wire and connect the
sensor (K615) signal circuit to the sensor (K690) return circuit at the
sensor connector.
Did the DTC P0072 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/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
Page 484 of 5267

When Monitored:
Engine running.
Set Condition:
Fuel pressure is above a calibrated value for a calibrated amount of time.
Possible Causes
FUEL CONTROL ACTUATOR (FCA)
FUEL PRESSURE SENSOR
INTERMITTENT CONDITION
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.Fuel Pressure Sensor
Using the scan tool, compare the scan tool reading for fuel pressure set point to the scan tool reading for actual fuel
pressure.
Does the actual fuel pressure correlate with the fuel pressure setpoint while operating the engine over
various operating conditions?
Ye s>>
Go To 2
No>>
Check the electrical connector of the Fuel Control Actuator, if the connection is tight, replace the fuel
control actuator.
Perform POWERTRAIN VERIFICATION TEST VER - 2 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING).
2.FUEL PUMP
Turn the ignition on.
Disconnect the Electronic Fuel Control Actuator connector.
Connect an incandescent test light across the Fuel Control Actuator driver pin and the Fuel Control Actuator return
wire at the fuel control actuator connector.
Observe the test light.
The ECM will perform a self test of the circuit which should momentarily flash the test light brightly, one time,
approximately 20 seconds after being connected.
NOTE: Compare test light brightness to that of a direct connection to the battery.
Did the light flash brightly?
Ye s>>
Replace the fuel pump.
Perform POWERTRAIN VERIFICATION TEST VER - 2 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Refer to the INTERMITTENT CONDITION Symptom (Diagnostic Procedure). (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
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P0106-INLET AIR PRESSURE SENSOR RATIONALITY
For a complete wiring diagramRefer to Section 8W.
Page 486 of 5267

When Monitored:
When the ignition is on.
Set Condition:
The Inlet air pressure is above a calibrated threshold.
Possible Causes
INLET AIR PRESSURE SENSOR
INTERMITTENT CONDITION
TROUBLESHOOT OTHER DTC’S FIRST
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.TROUBLESHOOT OTHER DTC’s FIRST
Using the Scan tool, check for additional DTC’s.
Do you have any other air pressure related DTC’s?
Ye s>>
Troubleshoot other DTC’s First.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 2
2.INLET AIR PRESSURE SENSOR
Using the scan tool, monitor the Inlet air pressure sensor values.
Do the readings on the scan tool fluctuate slightly?
No>>
Replace the Inlet Air Temperature/ Pressure sensor.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
Ye s>>
Refer to the INTERMITTENT CONDITIONSymptom (Diagnostic Procedure).
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
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P0107-INLET AIR PRESSURE SENSOR VOLTAGE TOO LOW
For a complete wiring diagramRefer to Section 8W.
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When Monitored:
With the ignition on and battery voltage greater than 10.4 volts.
Set Condition:
The circuit voltage to the ECM falls below a calibrated threshold for a certain period of time.
Possible Causes
OTHER DTC’S PRESENT
INLET AIR PRESSURE SENSOR
INLET AIR SENSOR (K616) SIGNAL CIRCUIT SHORTED TO THE (K690) RETURN CIRCUIT
INLET AIR PRESSURE SENSOR (K668) SUPPLY CIRCUIT SHORTED TO THE RETURN CIRCUIT
(K616) SIGNAL CIRCUIT OPEN
(K668) 5-VOLT SUPPLY CIRCUIT OPEN
(K616) SIGNAL CIRCUIT SHORTED TO GROUND
(K668) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
ECM
INTERMITTENT CONDITION
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.OTHER DTC’S PRESENT
Ignition on, engine not running.
With the scan tool, read DTCs.
Do you have multiple DTC’s?
Ye s>>
Repair other DTC’s first.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 2
2.SENSOR VOLTAGE
Disconnect the Inlet Air Pressure sensor harness connector.
Check connectors - Clean/repair as necessary.
Measure the voltage between the (K668) 5-volt supply circuit and
(K690) return circuit of the sensor harness connector.
Is the voltage between 4.5 and 5.5 volts?
Ye s>>
Go To 3
No>>
Go To 5
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3.INLET AIR PRESSURE SENSOR
While monitoring scan tool, use a jumper wire to connect the (K668)
5-volt supply circuit with the (K616) signal circuit at the sensor harness
connector.
Does the scan tool show a pressure sensor out of range high
DTC?
Ye s>>
Replace the Inlet Air Temperature/Pressure sensor.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
No>>
Go To 4
4.INLET AIR PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO THE RETURN CIRCUIT
Turn the ignition off.
Disconnect the ECM harness connector.
Check connectors - Clean/repair as necessary.
Measure the resistance between the (K616) signal circuit and (K690)
return circuit in the Inlet Air pressure sensor harness connector.
Is the resistance greater than 100K Ohms?
Ye s>>
Go To 5
No>>
Repair or replace wiring harness.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
5.SENSOR (K668) 5-VOLT SUPPLY CIRCUIT SHORTED TO THE (K690) RETURN CIRCUIT
Measure the resistance between the (K668) 5-volt supply circuit and
(K690) return circuit in the Inlet Air Pressure sensor harness connector.
Is the resistance greater than 100K Ohms?
Ye s>>
Go To 6
No>>
Repair the short or replace the harness.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
Page 490 of 5267
6.(K616) SIGNAL CIRCUIT OPEN
Measure the resistance between the (K616) signal circuit in the Inlet Air
Pressure sensor harness connector and the (K616) signal circuit in the
ECM harness connector.
Is the resistance less than 10 Ohms?
Ye s>>
Go To 7
No>>
Repair or replace the open wiring harness.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
7.(K668) 5-VOLT SUPPLY CIRCUIT OPEN
Measure the resistance between the (K668) 5-volt supply circuit in the
Inlet Air Pressure sensor harness connector with the (K668) 5-volt sup-
ply circuit in the ECM harness connector.
Is the resistance less than 10 Ohms?
Ye s>>
Go To 8
No>>
Repair or replace the Engine harness.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)