Powertrain, generic · Hybrid propulsion

P0A57 Drive Motor B Current Sensor Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0A57 is set when the signal of the drive motor B current sensor stays below its valid range, usually from a signal line shorted to ground, a missing sensor supply or a failed Hall element. No manufacturer documents P0A57 publicly. A Toyota patent explains the risk of this failure: a sensor held in its ground-short range reports much less current than really flows, the current controller raises its output and can drive the inverter into overcurrent; the system described therefore opens the system relays and warns the driver once the condition repeats. CARB requires out-of-range checks for hybrid input components. P0A58 is the high side, P0A55 the general circuit code, P0A56 plausibility, P0A53 the same check on motor A. Motor B is shut down.

Likely causes

Sensor signal line shorted to ground
Sensor supply voltage missing
Hall element of the current sensor failed

Symptoms

  • Hybrid warning and MIL
  • Drive motor B or the whole high-voltage system switched off

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€300–4,500
Time1–6 h

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

Parts involved

drive motor b current sensorwiring harnesshybrid control module

Related codes

P0A58P0A55P0A56P0A53P0A5B

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