Powertrain, generic · Hybrid propulsion

P0A3F Drive Motor A Position Sensor Circuit

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

The rotor position of a traction motor is read by a resolver: one excitation coil and two pickup coils that return sine and cosine signals. P0A3F is the basic circuit code for motor A and mostly means the signal is gone. GM sets it when the sine or cosine amplitude drops below 2.3 V (Type A, one trip in the 2011 and 2016 tables); Mitsubishi (2023 Outlander PHEV front motor) watches the excitation voltage and fails it outside 1.0 to 2.86 V for 0.14 s. Field causes: a spread terminal at the X2 connector of the Chevrolet Bolt, low 12 V supply on the 2014 Subaru XV Crosstrek Hybrid (software fix), Stellantis Pacifica Hybrid. P0A40 covers a degraded signal. Expect lost propulsion or no electric drive.

Likely causes

Spread or poorly seated terminal at the resolver connector (documented on the Chevrolet Bolt)

Open or shorted excitation, sine or cosine wire between motor and inverter

Low 12 V auxiliary battery voltage disturbing the motor control module (Subaru, fixed by reprogramming)

Resolver coil failed inside the motor

Faulty resolver excitation or input stage in the inverter/motor control module

Symptoms

Sudden loss of propulsion, sometimes normal again after a restart
MIL and hybrid/EV system warning on
Vehicle will not enter ready mode or electric drive is disabled

Repair estimate

DifficultyShop_onlyWorkshop job

Parts and labour€150–6,000

Time1–10 h

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

Parts involved

drive motor a position sensorwiring harnesshybrid control module

References: gsi.ext.gm.com, gsi.ext.gm.com, mitsubishitechinfo.com, static.nhtsa.gov.