A failed alternator. Damaged wiring or a corroded connector at the alternator. A blown fuse in the charging circuit.

P0620 Generator Control Circuit

Q: What does P0620 mean?

P0620 means there's a fault in the circuit that lets the engine computer control the alternator. Many vehicles let the engine computer control the alternator (generator) output. P0620 means it found a fault in that control circuit.

Electrical and modules

P0620 means there's a fault in the circuit that lets the engine computer control the alternator.

Many vehicles let the engine computer control the alternator (generator) output. P0620 means it found a fault in that control circuit.

Can I keep driving? Yes, but get it fixed soon.

The battery may not be charged properly. Get it checked soon to avoid being stranded.

Common causes

A failed alternator
Damaged wiring or a corroded connector at the alternator
A blown fuse in the charging circuit

Symptoms

Battery warning light
Low or high charging voltage
Electrical glitches

What to check first

Check charging voltage with the engine running.
Inspect the alternator's control connector and wiring.
Check charging system fuses.
Have the alternator tested.

What does P0620 mean on your vehicle?

The likely cause depends on your engine. iRepair researches your exact year, make, model and engine (service bulletins, recalls and owner reports) and tells you what to check first. Your first 3 questions are free.

Ask iRepair about P0620

No scanner? Most auto parts stores read check-engine codes for free.

Related codes

General guidance for P0620 on most vehicles. Some makers use the same code a little differently; confirm in the service information for your vehicle, put safety first, and see a professional when in doubt.