Powertrain, generic · Hybrid propulsion

P0A17 Motor Torque Sensor Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

Some electric drive units measure the torque on the motor or generator shaft directly, for example with a magnetostrictive sensor inside a hollow motor shaft as described in Honda patents for hybrid drive systems. The control unit uses that value to check the torque it commands. P0A17 is the general circuit fault of this sensor, set when the signal is missing or cannot be evaluated at all. No manufacturer documents P0A17 publicly. CARB requires a monitoring plan for drive motor faults that affect propulsion or emission strategies, which covers such feedback sensors. Plausibility is P0A18, low and high P0A19 and P0A20, intermittent P0A21. Expect reduced electric power and a hybrid warning.

Likely causes

Loose or corroded sensor connector at the drive unit
Damaged sensor wiring between drive unit and control module
Torque sensor or its excitation electronics failed, often only replaceable with the drive unit
Input stage of the hybrid or motor control module faulty

Symptoms

  • Hybrid system warning light
  • Electric drive power limited or electric drive disabled
  • Higher fuel consumption because the engine runs more often

Repair estimate

DifficultyHardWorkshop job
Parts and labour€100–3,000
Time1–8 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

motor torque sensorwiring harnesshybrid control module

Related codes

P0A18P0A19P0A20P0A21

References: patents.google.com, law.cornell.edu.