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
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Generator F-Terminal Circuit
Diagnostic Fault Information
Circuit/System Description
The engine control module (ECM) uses the generator field duty cycle control circuit, or F-terminal circuit, to monitor the duty cycle of the generator. The generator field duty cycle control 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 control 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 control 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, for the Ignition ON test.
* Engine running, engine speed less than 3 000 RPM for the RUN test.
Conditions for Setting the DTC
* DTC P0621 is not set.
* Ignition ON engine OFF, the ECM detects a PWM signal that is greater than 65% for 5 s.
* Engine running, the ECM detects a PWM signal that is less than 5% for 15 s.
Action Taken When the DTC Sets
DTC P0622 is a C type DTC.
Conditions for Clearing the DTC
DTC P0622 is a C type DTC.
Reference Information
Schematic Reference
Starting and Charging Schematics Electrical Diagrams
Connector End View Reference
Component Connector End Views Sunshade - Left (DH6)
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
Engine running, observe the scan tool Generator - F Terminal Control Circuit parameter. The Generator - F Terminal Control Circuit parameter should display between 5-95% depending on the actual turned on accessories.
Circuit/System Testing
1. Verify that a test lamp illuminates between the G13 Generator B+ output circuit terminal X2 and ground.
• If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
2. Ignition OFF, disconnect the X1 harness connector at the G13 Generator and the appropriate harness connector at the K20 Engine Control Module.
3. Test for less than 5 ohms between the X1 harness connector F-terminal and the harness connector at the K20 Engine Control Module as listed below:
* LBY - X2 terminal 49
* LBQ, LBR or LBS - X2 terminal 77
* LDE or 2H0 - X1 terminal 21
* LBW - X1 terminal 30
* LLU - X2 terminal 65
* LUJ - X3 terminal 17
* LHU - X2 terminal 55
• If not the specified value, test the F-terminal circuit for an high/open resistance.
4. Test for infinite resistance between the G13 Generator harness connector F-terminal and ground.
• If less than the specified range, test for short to ground or a short to voltage.
5. Connect the harness connector at the K20 Engine Control Module.
6. Adapt the G13 Generator L-terminal to the X1 harness connector L-terminal.
7. Engine run at 2 500 RPM, verify the battery voltage is 12.6-15 V.
• If not the specified value, refer to Charging System Test Testing and Inspection. If the circuit tests normal, test the G13 Generator before replacing.
8. If the circuit tests normal, replace the K20 Engine Control Module.
Component Testing
Dynamic Test
1. Connect a oscilloscope at the G13 Generator terminal B+ X1 and the G13 Generator generator housing.
2. Engine run at 2 500 RPM.
3. Compare the pictured signal with the following references Generator Oscilloscope Information Component Tests and General Diagnostics.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Generator Replacement (LE9) Generator Replacement (LE9)Generator Replacement (LF1) Generator Replacement (LF1)
* Control Module References Control Module References for ECM replacement, programming and setup