Pinpoint Test D : P0625, P0626: Notes
Diagnostic Overview
Diagnostics in this article assume a certain skill level and knowledge of Ford-specific diagnostic practices. Refer to Diagnostic Methods in Service Information for more information.
Refer to Charging System for schematic and connector information.
Normal Operation and Fault Conditions
The PCM monitors the generator output via the generator monitor (GENMON) circuit (generator field terminal circuit). If the PCM cannot read the GENMON circuit due to an open or short to ground, when the engine speed is greater than 2, 000 Revolutions Per Minute (RPM), the generator defaults to a steady voltage of 13.5 volts and the PCM sends a request to the IPC to illuminate the charging system warning indicator. A GENMON duty cycle of 3% or less indicates a short to ground fault is present and results in DTC P0625 setting in the PCM. A GENMON duty cycle of 98% or more indicates an open or short to voltage fault is present and results in DTC P0626 setting in the PCM.
DTC Fault Trigger Conditions
| DTC | Description | Fault Trigger Conditions |
|---|---|---|
| P0625 | Generator Field Terminal Circuit Low | The PCM sets this DTC if the GENMON circuit is shorted to ground, the "A" sense circuit is open or the B+ circuit is open. This DTC also sets by a faulted PCM or generator. |
| P0626 | Generator Field Terminal Circuit High | The PCM sets this DTC if the GENMON circuit is open or shorted to power. This DTC can also set by a faulted PCM or generator. |
Possible Sources
- Battery
- Engine, generator and battery grounds
- Fuses
- Generator
- PCM
- Wiring, terminals or connectors
Visual Inspection and Diagnostic Pre-checks
- Inspect for abnormal ignition-off current drain(s).
- Inspect the battery.
- Inspect for loose or corroded connections.
- Inspect high current BJB for loose or corroded connections.