P0A21Motor Torque Sensor Circuit Intermittent
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- Here the torque sensor on the traction motor shaft delivers a signal that drops out or jumps for short moments instead of failing permanently. Such shaft sensors, as in the Honda patent with a sensor inside a hollow motor shaft, sit in an area with strong electromagnetic fields and vibration, so loose terminals, chafed wires and interference are the usual suspects. P0A21 sets when the control unit counts too many implausible signal changes. No manufacturer documents P0A21 publicly; CARB demands an approved drive motor monitor. Steady faults would show as P0A19 or P0A20. The warning may come and go.
- What you may notice
- Hybrid warning that appears and disappears
- Brief loss of electric assist
- Likely causes
- LikelyLoose or fretted terminal in the sensor connector
- PossibleChafed sensor wiring that shorts briefly under vibration
- RareDamaged shield letting inverter noise into the signal
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €100 – €3,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.