P0A55Drive Motor B Current Sensor Circuit
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P0A55 is the general circuit fault of the current sensor that measures the current of drive motor B, typically the second traction motor, for example on a rear axle. The inverter needs this signal for torque control and to protect its power switches. No manufacturer documents P0A55 publicly. A Toyota patent shows the principle behind such checks: a control sensor and a monitoring sensor watch the same motor current, and a sensor stuck in its ground-short range or a lasting gap between the two leads to the relays opening. CARB requires circuit checks of hybrid input components. P0A56 is plausibility, P0A57/P0A58 low and high; P0A51 is the same fault on motor A. Usually drive motor B is switched off and the car drives on reduced power.
- What you may notice
- Hybrid or electric drive warning with MIL
- Drive motor B disabled, loss of electric all-wheel drive or reduced power
- Likely causes
- LikelyCurrent sensor of drive motor B failed (usually inside the inverter)
- PossibleSensor supply or signal line interrupted or shorted
- RareEvaluation circuit on the motor B control board faulty
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €300 – €4,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.