Powertrain, generic · Hybrid propulsion

P0CDC Drive Motor A Position Sensor Circuit C Low

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

P0CDC reports that circuit C of the rotor position sensor on drive motor A reads below its permitted window. Typical reasons are a short to ground, a short between windings or a low-resistance path through moisture in the connector. For circuits A and B GM shows how such a test works: the motor control processor compares the sensed resolver voltage with a threshold and sets a Type B code when it stays out of range for 0.25 s within a 0.375 s window (P0C52, P0C5C). No manufacturer publicly documents the circuit C version, and what that circuit carries is not published. As soon as the angle signal becomes unreliable, the inverter reduces or stops electric drive torque, and regeneration may be cut as well. Check plug and harness to the inverter before replacing parts. The high fault is P0CDD.

Likely causes

Circuit C wire shorted to ground or to another resolver wire

Moisture or corrosion in the resolver connector

Resolver winding internally shorted

Symptoms

Hybrid system warning and MIL
Electric drive limited, engine runs instead
Reduced or no 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: gsi.ext.gm.com, law.cornell.edu, en.wikipedia.org.