P0622
DTC P0622 (Gasoline)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
DTC P0622
- Generator F-Terminal Circuit
Diagnostic Fault Information
Typical Scan Tool Data
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
* The engine is running.
* The battery voltage is 9.5-18 V.
Conditions for Setting the DTC
The GEN F-Terminal Signal is less than 5 percent for 30 seconds.
Action Taken When the DTC Sets
* The charge indicator turns ON.
* The driver information center (DIC) displays the SERVICE BATTERY CHARGING SYSTEM message.
Conditions for Clearing the DTC
* The DTC will pass when the condition for setting the DTC is no longer present.
* A history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
* The charge indicator and DIC message will remain ON until the DTC passes or is cleared, even if the ignition is cycled.
Reference Information
Schematic Reference
Starting and Charging Schematics Electrical Diagrams
Connector End View Reference
Component Connector End Views 1-2 Shift Solenoid (SS) Valve (M30)
Description and Operation
Charging System Description and Operation Description and Operation
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON, engine OFF, observe the scan tool ECM GEN-F Terminal Signal parameter. The parameter should read 0%.
2. Engine running, observe the scan tool ECM GEN-F Terminal Signal parameter. The parameter should read between 5 and 99%.
Circuit/System Testing
1. Verify that a test lamp illuminates between the B+ circuit terminal 1 X2 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 X1 harness connector at the generator.
3. Ignition ON, verify the scan tool ECM GEN-F Terminal Signal parameter is 0%.
• If greater than the specified value, test the field duty cycle circuit terminal 2 X1 for a short to voltage. If the circuit tests normal, replace the ECM.
4. Connect a test lamp between the field duty cycle circuit terminal 2 X1 and B+. Verify the scan tool ECM GEN-F Terminal Signal parameter is greater than 95%.
• If less than the specified range, test the circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
5. If all circuits test normal, test or replace the generator.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Generator Replacement (V6) Generator ReplacementGenerator Replacement (V8) Generator ReplacementGenerator Replacement (Diesel) Generator Replacement
* Control Module References Control Module References for ECM replacement, setup, and programming.