Powertrain, generic · Hybrid propulsion

P0CDA Drive Motor A Position Sensor Circuit C

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

P0CDA belongs to the rotor position sensor of drive motor A, normally a resolver: an excited stator winding induces signals in pick-up windings so the motor controller can work out rotor angle and speed. SAE counts the circuits of this sensor as A, B and C; GM, for instance, assigns circuit A to the S1/S3 winding and circuit B to S2/S4. What circuit C carries is not described in any public manufacturer document; the excitation winding or an additional signal path would be plausible, but neither is confirmed. No manufacturer publicly documents P0CDA, so CARB's demand to monitor electric drive inputs for circuit faults is the basis. Without a trustworthy angle the inverter cannot control torque, and the system limits or stops electric drive. Plausibility faults are P0CDB, low and high P0CDC and P0CDD.

Likely causes

Loose, corroded or damaged resolver connector between motor and inverter

Damaged resolver wiring

Resolver winding of circuit C defective

Evaluation circuit in the motor control module faulty

Symptoms

Hybrid system warning and MIL
Electric drive limited or unavailable, engine runs more
Reduced regenerative braking

Repair estimate

DifficultyHardWorkshop job

Parts and labour€100–2,500

Time1–6 h

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

Parts involved

drive motor a position sensor cwiring harnesshybrid control module

References: law.cornell.edu, gsi.ext.gm.com, en.wikipedia.org.