What it means
The voltage signals of throttle/pedal position channels B and G do not correlate within the calibrated tolerance. One sensor element drifted or harness shows offset between channels.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
- The engine or gearbox may go into limp mode
How it works
The throttle or pedal assembly uses multiple position-sensor channels so the control module can check driver demand and throttle position for agreement. P2AD2 sets when channels B and G differ beyond their calibrated correlation tolerance, which can happen if either signal drifts or their wiring introduces an offset.
Common causes
Most likely first.
- Sensor channel B or G drifted
- Harness offset between channels
Symptoms
- Check engine light on
- Reduced throttle response, possible limp mode
- Hesitation or surging
- Idle too high or too low
How to diagnose it
- Read freeze-frame data and live throttle or pedal position values to see when the B-to-G disagreement occurs and whether it follows pedal movement.
- Inspect the throttle body or pedal assembly connectors and the B and G channel wiring for loose pins, corrosion, damage, or poor grounds.
- With a scan tool, compare B and G readings while slowly moving the pedal or throttle through its range and note whether one channel jumps or lags.
- Check the B and G signal, reference, and ground circuits for opens, shorts, or voltage drop using the vehicle wiring diagram and manufacturer's specification.
- If the wiring checks out, test the relevant throttle or pedal sensor assembly and replace it only if its B or G channel fails the manufacturer's specification.
Common fixes
- Repair loose, corroded, or damaged connectors and wiring affecting channels B and G.
- Repair a poor sensor ground or signal-circuit connection causing an offset.
- Replace the faulty throttle or pedal position sensor assembly if channel B or G is out of specification.
- Clear the code and confirm both channels track within tolerance during a road or functional test.
Can I keep driving?
Drive only as needed to reach a safe place or repair facility if throttle response is reduced or erratic; avoid fast traffic and hard acceleration. The module may limit power, and continued operation with unpredictable throttle response can be unsafe.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.