P0625

DTC P0625

Diagnostic Instructions
^ Perform the [Diagnostic System Check - Vehicle Diagnostic Information] prior to using this diagnostic procedure. Diagnostic System Check - Vehicle Diagnostic Information
^ Review [Strategy Based Diagnosis] for an overview of the diagnostic approach. Strategy Based Diagnosis
^ [Diagnostic Procedure Instructions - Vehicle Diagnostic Information] provides an overview of each diagnostic category. Diagnostic Procedure Instructions - Vehicle Diagnostic Information

DTC Descriptor
DTC P0625 Generator F-Terminal Circuit Low Voltage - 3.6L (LY7)

Diagnostic Fault Information






Typical Scan Tool Data

GEN F-Terminal Signal -ECM






Circuit/System Description
The engine control module (ECM) uses the generator field duty cycle signal circuit, or F-terminal circuit, to monitor the duty cycle of the generator. The generator field duty cycle signal circuit connects to high side of the field windings in the generator. A pulse width modulated (PWM) high side driver in the voltage regulator turns the field windings ON and OFF. The ECM uses the PWM signal input to determine the generator load on the engine. This allows the ECM to adjust the idle speed to compensate for high electrical loads. The ECM monitors the status of the generator field duty cycle signal circuit. When the key is in the RUN position and the engine is OFF, the ECM should detect a duty cycle near 0 percent. When the engine is running, the duty cycle should be between 5-99 percent.

Conditions for Running the DTC
^ The vehicle speed is above 8 km/h (5 mph).
^ The engine speed is less than 3,000 RPM.

Conditions for Setting the DTC
The ECM detects a pulse width modulated (PWM) signal less than 5 percent for 15 seconds.

Action Taken When the DTC Sets
^ The ECM will command the charge indicator to be illuminated on the instrument panel cluster (IPC).
^ The driver information center (DIC) will display the SERVICE BATTERY CHARGING SYSTEM message.
^ The ECM will not illuminate the malfunction indicator lamp (MIL).
^ The ECM will store conditions, which were present when the DTC set as Fail Records data only.

Conditions for Clearing the DTC
DTC P0625 is a C type DTC.

Circuit/System Verification
Engine running, observe the scan tool GEN-F Terminal Signal parameter. The GEN-F Terminal Signal parameter should be between 5-99 percent.

Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the generator.
2. Ignition ON engine OFF, observe the scan tool GEN-F Terminal Signal parameter, while repeatedly probing the generator field duty cycle circuit with a test lamp connected to battery positive voltage.The parameter should change from 0 percent to 99 percent.
^ If the parameter was not affected by the test lamp, test the GEN-F Terminal Signal circuit terminal 2 for a short to ground or an open/high resistance. If the circuit tests normal, then replace the ECM.

3. If the circuit tests normal, then replace the generator.

Repair Instructions
Perform the [Diagnostic Repair Verification - Vehicle Diagnostic Information] after completing the diagnostic procedure. Diagnostic Repair Verification - Vehicle Diagnostic Information
^ [Generator Replacement]