2010 Cadillac CTS Sedan AWD V6-3.6L Page 1525
瀚慖f greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM.
瀚慖f less than the specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal replace
the ECM.
4. If the circuits test normal, replace the generator.
LLT Engine
1. Verify that a test lamp illuminates between the generator B+ X2 and ground.
瀚慖f 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 X1 harness connector at the generator.
3. Ignition ON, test for less than 1 V between the control circuit terminal 1 and ground.
瀚慖f greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM.
4. Engine running, test for greater than 3.5 V between the control circuit terminal 1 and ground.
瀚慖f less than the specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal replace
the ECM.
5. If the circuits test normal, replace the generator.
Repair Instructions
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
P0622
DTC P0622
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 Descriptor
DTC P0622
- Generator F-Terminal Circuit
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
