2010 Cadillac Truck SRX FWD V6-3.0L Page 1620

2010 Cadillac Truck SRX FWD V6-3.0L Page 1620

Repair Instructions

Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.

* Generator Replacement (LF1) (See: Starting and Charging/Charging System/Alternator/Service and Repair)Generator Replacement (LAU)

(See: Starting and Charging/Charging System/Alternator/Service and Repair)

* Control Module References (See: Testing and Inspection/Programming and Relearning) for ECM replacement, setup and programming

P0626

DTC P0625 or P0626

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System

Check - Vehicle) prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an

overview of the diagnostic approach.

* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure

Instructions) provides an overview of each diagnostic category.

DTC Descriptors

DTC P0625

- Generator F-Terminal Circuit Low Voltage

DTC P0626

- Generator F-Terminal Circuit High Voltage

Diagnostic Fault Information

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 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%.

Conditions for Running the DTC

P0625

* The engine is running.

* The engine speed is less than 3 000 RPM.

P0626

* The engine is not running.

* The ignition is in the ON position.

Conditions for Setting the DTC

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.

Action Taken When the DTC Sets