P0A21: Motor Torque Sensor Circuit Intermittent
What to do
Note when the warning appears — wet weather, rough roads, hard acceleration — and tell the workshop. With intermittent faults, the pattern of appearances often does more diagnostic work than the code itself.
What this code means
The motor torque signal is cutting in and out — valid readings interrupted by dropouts or jumps too fast to be real torque changes.
Intermittent codes are wiring codes until proven otherwise, and this range gives the usual suspects a specific home: the connector and harness run between the transaxle and the inverter, which lives low in the engine bay where water, vibration and road debris all reach it. A fault that comes and goes with bumps, damp mornings or engine movement is this harness until inspection says otherwise.
Likely causes
Start here
- Intermittent wiring fault · moderate
- Corroded or loose connector · easy
Less common
- Water ingress into connector · easy
- Chafed harness between transaxle and inverter · moderate
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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