P0123

Throttle/Pedal Position Sensor/Switch "A" Circuit High

Severity: High
Driving: Drive only to a garage

Throttle or pedal position sensor "A" is reporting a high signal - outside its valid range rather than merely inaccurate. A working sensor cannot physically produce a value outside the range, so this points at wiring or a failed sensor.

Possible causes

CommonShort or open circuit in the sensor wiring
CommonFailed sensor
PossibleDisconnected or corroded connector
PossibleLoss of the sensor's reference voltage or ground

What you might notice

Reduced power mode, often severe
Engine will not rev, or will not start
Warning light on
Unstable or very high idle

What to check, in order

Do not drive far with this fault. Reduced power can engage abruptly.
Check the connector is seated and free of corrosion and water.
Check the sensor's reference voltage and ground at the connector. Losing either produces a stuck-at-limit reading on a healthy sensor.
Check continuity of the signal wire back to the module - an open circuit and a short give the two opposite versions of this code.
Replace the sensor only once reference, ground and wiring are confirmed good.

Read this code from your own car

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Where this code sits

B · Body C · Chassis P · Powertrain U · Network and communication