Powertrain, generic (extended)

P2E20 Drive Motor A Phase Y Current Sensor Circuit Range/Performance

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

P2E20 is set when the phase Y current sensor of drive motor A reads within its electrical limits but not believably. No manufacturer documents P2E20 publicly. Besides the zero check, a current balance can expose a sensor with a wrong gain. GM's eAssist table checks whether motor DC current and the input current of the accessory power module match the battery pack current; a mismatch above 40 A in 90 of 96 samples, taken every 2.08 ms, sets the U-V-W correlation code P0BFD as two-trip Type B. While a single sensor code is active, GM skips that balance and runs current control in a mode that does not rely on the sensors. The Mitsubishi Electric patent that defines X/Y/Z windings measures all six phase currents one by one. A drifting sensor or a disturbed reference is likely. X and Z range faults: P2E1C, P2E24.

Likely causes

Gain error of the phase Y sensor

Zero offset of the phase Y sensor shifted

Disturbed reference voltage of the current sensors

Motor control software needing an update

Symptoms

Hybrid warning lamp and MIL
Less electric assist, torque not as requested
Motor whine or slight vibration

Repair estimate

DifficultyShop_onlyWorkshop job

Parts and labour€200–5,000

Time1–6 h

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

Parts involved

drive motor a phase y current sensorwiring harnesshybrid control module

References: gsi.ext.gm.com, image-ppubs.uspto.gov, law.cornell.edu.