Powertrain, generic (extended)

P2E21 Drive Motor A Phase Y Current Sensor Circuit Low

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

P2E21 records that the phase Y current sensor of drive motor A reports a value under the bottom of its scale. No manufacturer documents P2E21 publicly. GM's eAssist logic shows a clean way to test for this: the low and high checks of its U and W sensors run while PWM output is disabled, so the inverter is not switching and no phase current can flow. A reading below -440 A in 4 of 6 samples, one every 10.4 ms, then sets the U-phase code as two-trip Type B. Anything that far out at rest can only come from the measuring chain, for example a grounded signal line or a dead sensor supply. Too little real current in phase Y is a different fault, P2C6D. In a Mitsubishi Electric design, X, Y and Z form the second star-connected set. High side: P2E22; X and Z low: P2E1D, P2E25.

Likely causes

Phase Y sensor signal shorted to ground

Sensor supply voltage missing

Phase Y current sensor failed

Symptoms

Hybrid warning lamp and MIL
Electric drive limited
Engine runs more often than usual on hybrids

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.