P0620 fault code: what it means

P0620: Alternator (generator) control circuit fault. Battery may not charge properly.

Engine and gearbox (powertrain) · Costly if missed

Usual causes, most likely first

1. failed alternator or voltage regulator
2. control wiring or connector fault
3. ECM driver fault

P0620 by make

Not sure what P0620 means on your car? Ask Credov.

Before you clear it

Write the code down or photograph the scanner first. A code that comes straight back after clearing points to a fault that is still there. A car whose codes were cleared just before you arrived may be hiding one: the scanner's readiness monitors show "not ready" for a while after codes are cleared.

Researched by Credov from manufacturer and workshop sources. A fault code points to where a fault may be; a workshop confirms it with a diagnosis. Browse all fault codes.