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P0622 is a diagnostic trouble code (DTC) for "Generator Field "F" Control Circuit Malfunction". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.
This code is defined as the generator field “F” control circuit malfunctioning.
When the PCM (powertrain control module) logs a P0622 trouble code, it’s because it’s detected a problem with the generator field control circuit. The PCM uses the generator turn-on signal circuit to manage the generator. When it wants to take control, it sends a five-volt signal to the voltage regulator through the generator turn-on signal circuit.
This forces the voltage regulator to start controlling the generator field circuit. Once the PCM enables the generator, the voltage regulator independently controls the generator. However, during this process, if it notices something is wrong with the generator field circuit, this trouble code is stored.
Depending on the exact problem, it could be reported by the body control module, the antilock brake control module, the alternative fuel control module, the anti-theft module, the turbo control module, the instrument panel control module, the climate control module, the cruise control module, the traction control module, the proximity alert module, and the fuel injection control module. Others could report the problem too. The reason this is important is because it could take several incidents before the Check Engine light comes on. It all depends on the module that reports the issue to the PCM first.
One simple reason for the code could be a battery charge issue. Otherwise, these three causes are the most common:
The least likely reason would be that the PCM simply stored the code erroneously, but it is possible.
As we mentioned above, the Check Engine light should come on, but it might take more than one incident before this happens. In that case, a scan of the vehicle may show that the P0622 code is pending. Other symptoms are more serious. The battery could discharge, for one thing. Acceleration might become difficult. Fuel efficiency will probably suffer too.
When driving, you might find that shifting is a challenge. The engine may also stall out or even start vibrating. If you put it in idle, the engine may make a weird noise.
A qualified technician will begin their diagnosis by using an OBD-II scanner to find which codes have been logged by the PCM. After that, they’ll probably examine the wires and connectors before moving on and doing the same to the control modules.
The Control Area Network (CAN) will most likely need to be inspected as well, which could mean taking out every pin in the process. This would require the use of a diagnostic CAN scanner and memory-saving tool.
A lot of underlying issues could be playing a role in this code being stored. This is why the mechanic must take each code one at a time and fix them in this order by using the freeze frame feature of their OBD-II scanner.
The problem is fairly serious when you consider its impact on drivability. It could really cripple a car’s capabilities. That being said, the problem with the CAN could mean something more widespread is happening with the vehicle’s electrical functions which might represent a larger issue.
There are a few things a mechanic can do to clear this code:
There are a number of other routes a technician may take, though, depending on which module reported the problem and its status.
Aside from taking the trouble codes one at a time, the mechanic must also use resets to ensure that their efforts are actually fixing the problem.
YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6220.