Cruze

DTC P0625 or P0626

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 ignition is ON and the engine is OFF, the ECM should detect a duty cycle near 0%. When the engine is running, the duty cycle should be between 5-99%.

P0625

P0626

P0625

The ECM detects a pulse width modulated (PWM) signal less than 5% for 15 s.

P0626

The ECM detects a pulse width modulated (PWM) signal greater than 65% for 15 s.

DTC P0625 and P0626 are a C type DTCs.

DTC P0625 and P0626 are a C type DTCs.

Schematic Reference

Starting and Charging Schematics

Connector End View Reference

Component Connector End Views

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

Engine running, observe the scan tool Generator - F Terminal Signal parameter. The Generator - F Terminal Signal parameter should display between 5-99%.

1. Verify that a test lamp illuminates between the G13 Alternator B+ terminal 1 X1 and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

2. Ignition OFF, disconnect the X2 harness connector at the G13 Generator.
3. Ignition ON, verify the scan tool ECM Generator - F Terminal Signal parameter displays less than 5%.

⇒	If greater than the specified range, test the signal circuit terminal 2 for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.

4. Install a 3 A fused jumper wire between B+ and the signal circuit.
5. Verify the scan tool ECM Generator - F Terminal Signal parameter displays greater than 95%.

⇒	If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.

6. If the circuit tests normal replace the G13 Generator.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.