Service Information

Cruze

DTC P0626

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 P0626: Generator F-Terminal Circuit High Voltage

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
B+	P0625	P0625	-	-
Signal	P0625	P0625	P0626	-
Signal	P2500	-	P2501	-

Typical Scan Tool Data

GEN F-Terminal Signal

Circuit	Short to Ground	Open	Short to Voltage
Operating Conditions: Engine Running Parameter Normal Range: 5% to 99%
B+	0%	0%	-
Signal	0%	0%	99%

Circuit

Short to Ground

Open

Short to Voltage

Operating Conditions: Engine Running

Parameter Normal Range: 5% to 99%

B+

Signal

99%

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 ignition is ON.

•	The engine is not running.

Conditions for Setting the DTC

The ECM detects that the field duty cycle signal is greater than 65 percent for 5 seconds.

Action Taken When the DTC Sets

•	The charge indicator turns ON.

•	The driver information centre (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

•	The DTC will pass when condition for setting the DTC is no longer present.

•	The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.

Reference Information

Electrical Information Reference

•	Circuit Testing

•	Connector Repairs

•	Testing for Intermittent Conditions and Poor Connections

•	Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, engine OFF, observe the scan tool GEN-F Terminal Signal parameter. The reading should be less than 5%.
Engine running, observe the scan tool GEN-F Terminal Signal parameter. The reading should be greater than 5%.

Circuit/System Testing

Verify that a test lamp illuminates between the G13 generator B+ output circuit 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.

Ignition OFF, disconnect the X2 harness connector at the G13 generator.
Ignition ON, verify the scan tool GEN-F Terminal Signal is less than 5%.

⇒	If greater than the specified range, test the signal circuit terminal 2 X2 for a short to voltage. If the circuit tests normal, replace the K20 ECM.

Install a 3 A fused jumper wire between the signal circuit terminal 2 X2 and B+. Verify the scan tool GEN-F Terminal Signal is greater than 95%.

⇒	If less than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.

If all circuits test normal, test or replace the G13 generator.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

•	Generator Replacement : 2.0L Diesel LNP → 2.0L Diesel LLW → 1.4L LDD, LUH, and LUJ → 1.6L LXT,L2W → 1.6L LDE, LXV, LLU, 1.8L 2H0, and LUW

•	Control Module References for ECM replacement, setup, and programming