P129D

DTC P129D

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.

* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P129D
- Fuel Pump Driver Control Module Ignition 1 Switch Circuit Low Voltage

Diagnostic Fault Information






Circuit/System Description

The fuel pump power control module monitors the ignition voltage circuit in order to determine if the voltage is within the normal operating range.

Conditions for Running the DTC

The DTC runs continuously when the modules are awake.

Conditions for Setting the DTC

The fuel pump power control module Power Mode does not agree with the engine control module (ECM) Power Mode for 1 s.

Action Taken When the DTC Sets

DTC P129D is a Type A DTC.

Conditions for Clearing the DTC

DTC P129D is a Type A DTC.

Reference Information

Schematic Reference

Engine Controls Schematics (LHU) [1][2]Electrical Diagrams

Connector End View Reference

Component Connector End Views Sunshade - Left

Description and Operation

Fuel System Description Fuel System Description

Electrical Information Reference

* Circuit Testing Circuit Testing

* Connector Repairs Connector Repairs

* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections

* Wiring Repairs Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References Control Module References for scan tool information

Circuit/System Testing

1. Ignition ON.

2. Verify DTC P0562 is not set.

• If the DTC is set
Refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle.

• If the DTC is not set

3. Ignition OFF, disconnect the harness connector at the Fuel Pump Power Control Module, ignition ON.

4. Verify a test lamp illuminates between the ignition circuit terminal 6 and ground.

• If the test lamp does not illuminate and the circuit fuse is good

1. Ignition OFF, remove the test lamp.

2. Test for less than 2 ohms in the ignition circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse.

• If the test lamp does not illuminate and the circuit fuse is open

1. Ignition OFF, remove the test lamp.

2. Test for infinite resistance between the ignition circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.

• If infinite resistance, replace the Fuel Pump Power Control Module.

• If the test lamp illuminates

5. Replace the Fuel Pump Power Control Module.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the repair.

Fuel Pump Power Control Module Replacement Fuel Pump Power Control Module Replacement