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5.TOTALLY INTEGRATED POWER MODULE
NOTE: Before continuing, check the TIPM harness connector terminals for corrosion, damage, or terminal
push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors.
Pay particular attention to all Power and Ground circuits.
Were any problems found?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Replace the Totally Integrated Power Module in accordance with the Service Information.
Perform the BODY VERIFICATION TEST – VER 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
Page 802 of 5267
P0127F-FUEL PUMP CONTROL CIRCUIT 2 OVERCURRENT (TIPM)
For a complete wiring diagramRefer to Section 8W.
Page 803 of 5267

When Monitored:
With the ignition on. Battery voltage greater than 10.4 volts. TIPM requesting Fuel Pump operation.
Set Condition:
An overcurrent condition is detected in the fuel pump control output circuit. One Trip Fault. Three good trips to
turn off the MIL.
Possible Causes
TERMINAL DAMAGE OR CORROSION
FUEL PUMP MOTOR GROUND HIGH RESISTANCE
(A109) FUEL PUMP CONTROL OUTPUT CIRCUIT HIGH RESISTANCE
FUEL PUMP MOTOR
TIPM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.FUEL PUMP OPERATION
Ignition on, engine not running.
With a scan tool in the TIPM Actuators, actuate the Fuel Pump.
Is the Fuel Pump operating?
Ye s>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 2
2.VISUAL AND PHYSICAL CONNECTOR AND TERMINAL INSPECTION
Turn the ignition off.
Disconnect the C10 TIPM harness connector.
Disconnect the Fuel Pump Module harness connector.
Inspect the terminal and connector condition. Check for signs of corrosion build up or damage the would compro-
mise the terminal to controller pin connector.
NOTE: Make sure that all in-line connectors are inspected for corrosion and/or damage.
Visually inspect the wiring harness. Look for any chafed, pierced, pinched or partially broken wires hidden in the
wire insulation.
Were any of the above conditions found?
Ye s>>
Repair or replace as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 3
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3.(A109) FUEL PUMP CONTROL OUTPUT CIRCUIT HIGH RESISTANCE
With a jumper wire, connect one end to the (A109) Fuel Pump Control
Output circuit in the Fuel Pump Module harness connector and the
other to a clean chassis ground.
Using a 12-volt test light to battery voltage, probe the (A109) Fuel Pump
Control Output circuit in the C10 TIPM harness connector.
NOTE: The test light should be illuminated and bright. Compared
the brightness to that of a direct connection to the battery.
Does the test light illuminate brightly.
Ye s>>
Go To 4
No>>
Repair the excessive resistance in the (A109) Fuel Pump
Control Output circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE).
4.FUEL PUMP MOTOR GROUND CIRCUITS
Using a 12-volt test light to battery voltage, probe the (Z927) and (Z210)
Fuel Pump Motor Ground circuits in the Fuel Pump Motor harness con-
nector.
NOTE: The test light should be illuminated and bright. Compared
the brightness to that of a direct connection to the battery.
Does the test light illuminate brightly.
Ye s>>
Go To 5
No>>
Repair the excessive resistance in the Fuel Pump Motor
Ground circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
5.FUEL PUMP CONTROL OUTPUT FROM TIPM
Reconnect the C10 TIPM harness connector.
Ignition on, engine not running.
With a scan tool in the TIPM Actuators, actuate the Fuel Pump.
Using the 12-Volt test light connected to ground, probe the (A109) Fuel
Pump Control Output circuit in the Fuel Pump Module harness connec-
tor.
Does the test light illuminate brightly?
Ye s>>
Replace the Fuel Pump Module
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Replace the TIPM in accordance with the Service Informa-
tion.
Perform the BODY VERIFICATION TEST – VER 1. (Refer
to 9 - ENGINE - STANDARD PROCEDURE)
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P1652-J1850 SHORT TO GROUND
For a complete wiring diagramRefer to Section 8W.
Page 806 of 5267
When Monitored:
While the ignition is on.
Set Condition:
The ECM detects a short to ground on the J1850.
Possible Causes
ECM
(D25) J1850 SHORTED
COMMUNICATION
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.ECM
Turn the ignition off.
Disconnect the ECM harness connectors.
NOTE: Check connectors - Clean/repair as necessary.
Measure the resistance between the (D25) J1850 circuit in the ECM
harness connector and battery negative.
Is the resistance less than 10 Ohms?
Ye s>>
Go To 2
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 807 of 5267
2.(D25) J1850 SHORTED
Measure the resistance between the (D25) J1850 circuit and all other
circuits in both ECM connectors.
Is the resistance greater than 100k ohms?
Ye s>>
Refer to the Body Diagnostic book Communications section.
No>>
Repair (D25) J1850 shorted to another circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
Page 808 of 5267
P2121-PPS CONFORMANCE ERROR
For a complete wiring diagramRefer to Section 8W.