2010 Cadillac CTS Sedan AWD V6-3.6L Page 1527
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Generator Replacement (LF1/LLT) (See: Starting and Charging/Charging System/Alternator/Service and Repair)Generator Replacement
(LSA) (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
P0625
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 percent. When the engine is
running, the duty cycle should be between 5-99 percent.
Conditions for Running the DTC
P0625
* The engine is running.
* The engine speed is less than 3000 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 percent for 15 seconds.
P0626
The ECM detects a pulse width modulated (PWM) signal greater than 65 percent for 15 seconds.
Action Taken When the DTC Sets
DTC P0625 and P0626 are a C type DTCs.
