P2123 fault code: what it means

P2123: Accelerator pedal position sensor A circuit high. Limp mode possible.

Engine and gearbox (powertrain) · Costly if missed

Usual causes, most likely first

accelerator pedal sensor
wiring fault

P2123 by make

Honda

Accelerator pedal position sensor A circuit high. Limp mode possible.

Usual causes: accelerator pedal sensor; wiring fault

Isuzu

Accelerator pedal sensor 1 circuit high.

Usual causes: pedal sensor; wiring

Mazda

Accelerator pedal position sensor No.1 circuit high. Limp mode with limited power.

Usual causes: accelerator pedal assembly; wiring or connector fault

Subaru

Accelerator pedal sensor D circuit high.

Usual causes: accelerator pedal assembly; wiring fault

What the repair usually costs

Automatic transmission rebuild, 6-speed and up (sent to specialist)NZ$7,190–NZ$13,080 · A$6,190–A$11,830
DSG / dual-clutch mechatronic unit replacement (new or reman)NZ$4,300–NZ$7,160 · A$3,750–A$6,390
DSG mechatronic repair / rebuild (unit sent to specialist)NZ$2,070–NZ$4,800 · A$1,890–A$4,250
Electronic throttle body replaceNZ$470–NZ$1,290 · A$440–A$1,190

Not sure what P2123 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.