Powertrain, generic · Hybrid propulsion

P0A6B Drive Motor B Phase V Current High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0A6B is stored when phase V of drive motor B reports more current than the operating state allows. No manufacturer documents P0A6B publicly. Two causes must be told apart: a real overcurrent from a shorted switch, a winding fault or an insulation breakdown, and a sensor that reads high because its gain or zero offset has drifted. Patents show how inverters separate them: Toyota compares a control sensor against a monitoring sensor and the commanded current, Caterpillar checks that the three phase currents still sum to about zero. CARB requires plausibility monitoring of electric drive components. P0A6A is the low side, P0A68 and P0A6E the U and W phases, P0A62 the motor A counterpart. The inverter shuts motor B down to protect itself.

Likely causes

Phase V current sensor gain or offset drifted high
Shorted power switch in the phase V leg
Winding or insulation fault in phase V of motor B

Symptoms

  • Hybrid warning and MIL
  • Motor B cut out, reduced acceleration

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€400–7,000
Time2–10 h

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

Parts involved

drive motor b phase vinverter

Related codes

P0A69P0A6AP0A68P0A6EP0A62P0A79

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