P2123Throttle/Pedal Position Sensor/Switch D Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P2123 is the high-voltage fault on pedal track D, usually an open sensor ground or a short to the 5 V reference or to battery voltage. GM's 2007 tables set it above 4.75 V (19 of 39 counts, Type A), a Bosch-based GM ECM from 2012 above 4.824 V lasting 0.2 s, and the 2014 VW Touareg above 4.89 V; Ford uses 4.75 V. A track pinned near the supply rail would read like a fully pressed pedal, so the controller rejects it, carries on with track E and caps engine output. GM PIP3783D lists the code among the very intermittent pedal faults on 2007-2014 full-size trucks and advises wiggling the harness and testing terminal tension. P2122 is the low counterpart, P2120 the general circuit code, P2128 the high fault on track E.
- What you may notice
- Engine warning lamp and reduced power message
- Limited throttle opening despite full pedal
- Fault may appear and vanish with harness movement
- Likely causes
- LikelyOpen or high-resistance ground return of the pedal sensor
- PossibleTrack D signal shorted to the 5 V reference or battery voltage
- PossibleInternal pedal sensor fault
- RareLoose or spread terminals at pedal or inline connector
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Easy · Often possible to do yourself.Typical cost: €20 – €350
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.