P2AD3Throttle/Pedal Position Sensor/Switch A/G Voltage Correlation
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P2AD3 compares tracks A and G. In GM's 2023 scheme A is the first sensor of the bank 1 throttle body and G the second sensor of the bank 2 unit, so the pair links both throttles of a V engine and can reveal that one plate is not where the other suggests. Mercedes-Benz is the documented user: on M177 V8s from the 2015 AMG C63 to the 2025 Maybach GLS 600, P2AD300 reads as an implausible relation between the A and G position values. Bulletin LI07.10-P-080384 already listed it in version 2 (May 2026) and blames raised contact resistance in the connectors M16/60 and M16/61 of the two throttle actuators. When P2135 or P2136 are stored alongside, a shared cause in the connectors is more likely than two failed throttles.
- What you may notice
- Check engine light on
- Possible loss of power or emergency throttle mode
- Likely causes
- LikelyRaised contact resistance in the connectors of both throttle actuators
- PossibleOne throttle body with a faulty position sensor
- RareFault on a shared sensor supply or ground
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €150 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.