P1503 fault code: what it means

P1503: Alternator load signal makes no sense. Charging problems may follow.

Engine and gearbox (powertrain) · Minor

Usual causes, most likely first

1. faulty alternator or regulator
2. wiring fault

P1503 by make

Not sure what P1503 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.