Fault codes › Powertrain › Generic (SAE standard) › Control module and its outputs
P0620 Generator control circuit
Needs attention Have it looked at soon. The car is usually driveable with care in the meantime.
What does P0620 mean?
P0620 is a generic powertrain code, defined by the SAE standard, so it means the same thing on every make and model: generator control circuit. It belongs to the control module and its outputs group of codes.
A control module stores the code when something it watches stays outside what it expects for long enough. On its own the code says which system complained, not which part has failed — the causes below, most likely first, are where to start.
Is it safe to drive with P0620?
Needs attention. Driveable short distances; watch for the battery warning.
Common causes of P0620
- Alternator control fault.
- Wiring between module and alternator.
Symptoms
- Charging warning.
- Unstable voltage.
What to check first
- Charging voltage.
- Control wiring continuity.
Can I just clear P0620?
You can, and the light goes out — but a fault that is still there sets the code again, often within a drive or two. Clearing also erases the freeze frame (what the engine was doing when the code was stored) and resets the emissions readiness monitors, so an MOT, smog or inspection test will wait until they have run again. Fix the cause first, then clear it, then watch whether it returns.
Read and clear P0620 from your iPhone with OBDTrip
Plug a Bluetooth OBD-II adapter into the car and OBDTrip reads every stored, pending and permanent code, explains each one in plain English like this, shows what the engine was doing when it was set, and clears the check engine light once the fault is fixed. It keeps a history of when each code comes back, and records every drive on its own from then on.
Needs a Bluetooth Low Energy adapter such as the Vgate iCar Pro — which adapters work with iPhone. Reading and clearing codes is part of an OBDTrip subscription.
Related codes
General guidance from OBDTrip's fault-code catalogue, not a diagnosis of your car. When a code points to brakes, steering, overheating or a flashing check engine light, have the car looked at before driving on.