P0622 Generator Field F Control Circuit Malfunction
OBD-II Trouble Code Technical Description
Generator Field F Control Circuit Malfunction
What does that mean?
This is a generic diagnostic trouble code (DTC) and applies to many OBD-II vehicles (1996-newer). That may include but is not limited to vehicles from Dodge, Jeep, Chevy, Ford, Land Rover, Toyota, Ram, etc. Although generic, the exact repair steps may vary depending on year, make, model and powertrain configuration.
A stored code P0622 means that the powertrain control module (PCM) has detected a malfunction with the generator field coil control circuit. The F simply reiterates the field coil control circuit is at fault.
The field coil is probably most recognizable from its windings which are visible through the vent holes on most alternators. The field coil surrounds the generator armature and remains stationary in the alternator housing.
The PCM monitors the continuity and voltage level of the generator field control circuit whenever the engine is running. The generator field coil is integral to generator operation and maintaining battery charge levels.
Each time the ignition is turned on and the PCM is energized, multiple controller self-tests are performed. In addition to running internal controller self-tests, the controller area network (CAN) is used to compare signals from each individual module to ensure that the various controllers are interfacing properly.
If a problem is detected in monitoring the generator field control circuit, a code P0622 will be stored and a malfunction indicator lamp (MIL) may be illuminated,. Depending upon the perceived severity of the malfunction, multiple failure cycles may be necessary for MIL illumination.
A typical alternator:
What is the severity of this DTC?
Internal control module codes be considered severe. A stored code P0622 could result in a variety of drivability concerns, including a no-start and/or dead battery condition.
What are some of the symptoms of the code?
Symptoms of a P0622 trouble code may include:
Engine drivability issues Engine stall when idling Inadvertent engine shutoff Delayed engine cranking Other stored codesWhat are some of the common causes of the code?
Causes for this code may include:
Faulty PCM PCM programming error Open or shorted generator field control circuit Defective alternator/generatorWhat are some P0622 troubleshooting steps?
A diagnostic scanner, a battery/alternator tester, a digital volt/ohmmeter (DVOM), and a source of reliable vehicle information will be required to diagnose a code P0622.
Consult your vehicle information source for technical service bulletins (TSB) that replicate the code stored, vehicle (year, make, model, and engine), and symptoms exhibited. If you find the appropriate TSB, it may yield helpful diagnostic.
Begin by connecting the scanner to the vehicle diagnostic port and retrieving all stored codes and freeze frame data. You will want to write this information down, just in case the code proves to be an intermittent one. After recording all pertinent information, clear the codes and test drive the vehicle until the code is reset or the PCM enters readiness mode. If the PCM enters readiness mode, the code is intermittent and will be more difficult to diagnose. The condition, which caused the P0622 to be stored, may even need to worsen before a diagnosis can be made. If the code is reset, continue with your diagnosis.
Use the battery/alternator tester to load-test the battery and make sure that it is sufficiently charged. If it is not, charge the battery as recommended and test the alternator/generator. Follow manufacturer’s recommended specifications for minimum and maximum voltage output requirements for the battery and alternator. If the alternator/generator is not chargin
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