P127F

P127F-FUEL PUMP CONTROL CIRCUIT 2 OVERCURRENT (TIPM)

P127F-Fuel Pump Control Circuit 2 Overcurrent (TIPM):

WHEN MONITORED
With the ignition on. Battery voltage greater than 10.4 volts. TIPM requesting A/C Clutch 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
- (Z904) Fuel pump ground high resistance
- (N1) Fuel pump control output circuit high resistance
- Fuel pump
- TIPM

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test

1. A/C CLUTCH OPERATION

Ignition on, engine not running.
With a scan tool in the TIPM Actuators, actuate the Fuel Pump.

Q: Is the Fuel Pump operating?

YES: Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition
Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 2

2. VISUAL AND PHYSICAL CONNECTOR AND TERMINAL INSPECTION

Turn the ignition off.
Disconnect the TIPM C7 harness connector.
Disconnect the Fuel Pump harness connector.
Inspect the terminal and connector condition. Check for signs of corrosion build up or damage the would compromise 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.

Q: Were any of the above conditions found?

YES: Repair or replace as necessary. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 3

3. (N1) FUEL PUMP CONTROL OUTPUT CIRCUIT HIGH RESISTANCE

With a jumper wire, connect one end to the (N1) Fuel Pump Control Output circuit in the A/C Clutch harness connector and the other to a clean chassis ground.
Using a 12-volt test light to battery voltage, probe the (N1) Fuel Pump Control Output circuit in the TIPM C7 harness connector.

NOTE: The test light should be illuminated and bright. Compared the brightness to that of a direct connection to the battery.

Q: Does the test light illuminate brightly.

YES: Go To 4
NO: Repair the high resistance in the (N1) Fuel Pump Control Output circuit. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

4. FUEL PUMP GROUND CIRCUIT

Using a 12-volt test light to battery voltage, probe the (Z904) Fuel Pump Ground circuit in the Fuel Pump harness connector.

NOTE: The test light should be illuminated and bright. Compared the brightness to that of a direct connection to the battery.

Q: Does the test light illuminate brightly.
YES: Go To 5
NO: Repair the excessive resistance in the (Z904) Fuel Pump Ground circuit. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

5. FUEL PUMP CONTROL OUTPUT FROM TIPM

Reconnect the TIPM C7 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 (N1) Fuel Pump Control Output circuit in the Fuel Pump harness connector.

Q: Does the test light illuminate brightly?

YES: Replace the Fuel Pump. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Replace the TIPM. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test