P1123 fault code: what it means

P1123: Accelerator pedal sensor shorted to battery positive.

Engine and gearbox (powertrain) · Costly if missed

Usual causes, most likely first

faulty accelerator pedal sensor
wiring short

P1123 by make

Land Rover

Accelerator pedal sensor shorted to battery positive.

Usual causes: faulty accelerator pedal sensor; wiring short

Porsche

Mixture adaptation on cylinders 1-3 hit its lean limit: that bank is running too rich and the DME cannot lean it further.

Usual causes: dirty or faulty MAF sensor; leaking injector; EVAP purge valve stuck open; fuel pressure too high

What the repair usually costs

MAF (mass air flow) sensor replaceNZ$170–NZ$660 · A$160–A$600
High-pressure fuel pump (GDI petrol or common-rail diesel)NZ$1,140–NZ$4,280 · A$1,060–A$3,800

Not sure what P1123 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.