Powertrain, generic · Hybrid propulsion

P0A5E Drive Motor A Phase U Current Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0A5E means too little current flows, or is sensed, in phase U of drive motor A, the classic sign of an open phase. GM describes the check for the motor control processor of the 2016 Chevrolet Volt and in its 2018 hybrid tables: with the inverter in normal PWM above 50 V and a squared current command above 900 A2 (2016) or 4,900 A2 (2018), the absolute U current is sampled while the rotor is within 30 degrees of the U phase axis; below 9 A for 0.4 s of a 0.6 s window, P0A5E sets as Type A, MIL on the first trip. Each phase is tested in turn as the rotor turns. A Caterpillar patent likewise spots a dead sensor by a phase reading near zero. P0A61 and P0A64 are phases V and W, P0A5F the high side, P0A5D the general U code.

Likely causes

Open circuit in the phase U cable, connector or terminal
Phase U current sensor reads zero
Phase U switch of the inverter not conducting
Open winding of phase U in drive motor A

Symptoms

  • MIL and propulsion system warning
  • Rough or reduced electric drive, possible engine-only operation

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€300–6,000
Time1.5–8 h

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

Parts involved

drive motor a phase uinverter

Related codes

P0A5DP0A5FP0A61P0A64P0A67

References: gsi.ext.gm.com, gsi.ext.gm.com, patents.google.com.