P0A66Drive Motor B Phase U Current
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P0A66 is the general fault code for the current in phase U of drive motor B, the second electric machine of a two-motor hybrid or an electric rear-axle motor. No manufacturer documents P0A66 publicly; GM, for instance, only uses the open-phase code P0A67 for this phase. The checks behind such a code are described in patents: a Caterpillar patent declares a phase sensor failed when the three phase currents no longer add up to roughly zero, and a Hyundai patent shows inverters that measure two phases and calculate the third. CARB requires circuit and rationality monitoring of electric drive components. P0A67 and P0A68 are the low and high variants, P0A69 and P0A6C cover phases V and W, P0A5D is the same code on motor A. Motor B is normally shut off.
- What you may notice
- Hybrid system warning and MIL
- Motor B switched off, less power or no electric all-wheel drive
- Likely causes
- LikelyPhase U current sensor of motor B failed (inside the inverter)
- PossiblePhase U high-voltage cable or terminal between inverter and motor B faulty
- PossibleInternal fault in the motor B power stage
- RareWinding fault in phase U of drive motor B
- 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 – €6,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.