Powertrain, generic · Hybrid propulsion

P0A18 Motor Torque Sensor Circuit Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

The motor torque sensor delivers an electrically valid signal, but the torque it reports does not match what the control unit expects from the commanded motor current, speed and operating state. Typical checks compare measured and estimated torque or look for an offset when no torque is applied. Honda patents show such a sensor mounted inside the hollow output shaft of a traction motor, where electromagnetic noise is a known accuracy issue. No manufacturer documents P0A18 publicly. CARB requires approved monitoring of drive motor faults that impair propulsion. P0A17 is the plain circuit fault; P0A19 and P0A20 are out of range low and high. The drive system usually limits electric torque.

Likely causes

Sensor offset or gain drifted, reading off against the torque model
Electrical interference on the signal from damaged shielding or ground
Missing or outdated calibration after module or drive unit replacement
Mechanical fault in the drive unit that changes the real torque

Symptoms

  • Hybrid system warning light
  • Reduced or uneven electric assistance
  • Engine runs more often, fuel use rises

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

P0A17P0A19P0A20P0A21

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