P0622
DTC P0622
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
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
* Ignition ON, engine OFF (Prior to Ignition ON, the ignition must have been OFF for at least 5 seconds).
* Engine running at less than 3,000 RPM.
Conditions for Setting the DTC
* DTC P0621 is not set.
* Ignition ON, engine OFF (Prior to Ignition ON, the ignition must have been OFF for at least 5 seconds), the ECM detects a PWM signal that is greater than 65% for 5 seconds.
* Engine running at less than 3,000 RPM-The ECM detects a PWM signal that is less than 5% for 30 seconds.
* If the DTC(s) are not currently set, reference the freeze frame/failure records to determine if the ignition ON, engine OFF or Engine running test failed.
* Operate vehicle within the conditions defined in the records to verify the DTC does not reset.
Action Taken When the DTC Sets
DTC P0622 is a C type DTC.
Conditions for Clearing the DTC
* Ignition ON, Engine OFF- Low / no PWM signal detected.
* Engine running - A 5-90% duty cycle is detected.
Reference Information
Schematic Reference
Starting and Charging Schematics [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views Outside Rearview Mirror - Driver
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
Note: Do not have a battery charger connected during the generator testing.
1. Engine running and head lamps ON.
2. Verify the scan tool Engine Control Module Generator F-Terminal Signal parameter changes between 5-90%.
• If the parameter does not change
Refer to Circuit/System Testing.
• If the parameter changes
3. All OK.
Circuit/System Testing
1. Verify a test lamp illuminates between the G13 Generator B+ circuit terminal A X2 and ground.
• If the test lamp does not illuminate and the circuit fuse is good
1. Remove the test lamp and disconnect the B+ cable at the G13 Generator.
2. Test for less than 2 ohms in the B+ circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse.
• If the test lamp does not illuminate and the circuit fuse is open
1. Remove the test lamp, disconnect the battery negative cable, and disconnect the G13 Generator B+ cable.
2. Test for infinite resistance between the B+ circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If the test lamp illuminates
2. Disconnect the X1 harness connector at the G13 Generator, engine running.
3. Verify the scan tool Engine Control Module Generator F-Terminal Signal parameter is less than 5%.
• If 5% or greater
1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
2. Test for less than 1 V between the signal circuit terminal 2 and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K20 Engine Control Module.
• If less than 5%
4. Install a 3 A fused jumper wire between the signal circuit terminal 2 and B+.
5. Engine running, verify the scan tool Engine Control Module Generator F-Terminal Signal parameter is greater than 95%.
• If 95% or less
1. Ignition OFF, remove the jumper wire, disconnect the harness connector at the K20 Engine Control Module.
2. Test for less than 2 ohms in the signal circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms
3. Test for infinite resistance between the signal circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K20 Engine Control Module.
• If greater than 95%
6. Test or replace the G13 Generator.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Generator Replacement (2.4L LEA) Service and RepairGenerator Replacement (2.0L LHU) Service and Repair
* Control Module References Control Module References for Engine Control Module replacement, programming, and setup