Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptor
DTC P129C: System Voltage High - FPDMDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
IGN/B+ | P129C | P129C | -- | -- |
Ground | -- | P129C | -- | -- |
Circuit/System Description
The fuel pump control module (FPCM) monitors the system voltage supplied to the fuel pump driver module (FPDM) to ensure that the voltage stays within the proper range. Damage to components, and incorrect data may occur when the voltage is out of range.
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
The FPCM detects that the system voltage is greater than 18 V for 5 seconds.
Action Taken When the DTC Sets
DTC P129C is a type A DTC.
Conditions for Clearing the DTC
DTC P129C is a type A DTC.
Diagnostic Aids
| • | A high voltage DTC in multiple modules indicates a concern in the charging system. |
| • | This DTC could be set by overcharging with a battery charger or jump starting. |
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Charging System Description and Operation
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Engine running, accessories OFF, measure and record the battery voltage at the battery terminals. The voltage should be between 12.6 and 15.0 V.
- If all circuits test normal, replace the FPDM.
| ⇒ | If not within the specified range, refer to Charging System Test. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Refer to Fuel Pump Flow Control Module Relay Replacement for Fuel Pump Flow Control Module Relay.
