P2AD1
Throttle/Pedal Position Sensor/Switch C/G Voltage Correlation
The voltage signals of throttle/pedal position channels C and G do not correlate within the calibrated tolerance. One sensor element drifted or harness shows offset between channels.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Symptoms
- Check engine light on
- Reduced throttle response, possible limp mode
- Hesitation or surging
- Idle too high or too low
Common causes
Ordered by how often each turns out to be the cause.
- Sensor channel C or G driftedCommon
- Harness offset between channelsPossible
Parts involved
- TPS Channel C
- TPS Channel G
- ECM
P2AD1 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.