Powertrain, generic · Hybrid propulsion

P0CDB Drive Motor A Position Sensor Circuit C Range/Performance

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

P0CDB flags circuit C of the drive motor A position sensor as present but implausible: its amplitude or phase, or the angle calculated from it, no longer agrees with the other circuits or with the observed motor speed. GM runs comparable tests on the main resolver signals, for example an amplitude check of the sine and cosine windings under P0A3F rated Type A, and limits for circuits A and B. No manufacturer publicly documents P0CDB itself, and none explains what circuit C carries; CARB requires rationality monitoring of electric drive inputs. Plausible causes are a resolver that has shifted on its mount, rotor bearing play, a winding or terminal whose values change with heat, or a controller calibration issue. Drivers usually see a hybrid warning and reduced electric power. Hard circuit faults are P0CDC and P0CDD.

Likely causes

Winding or terminal of the resolver changing its values when hot

Resolver shifted on its mount or rotor bearing play

Motor control module software or calibration

Symptoms

Hybrid system warning, MIL
Reduced electric power, engine starts in EV mode
Fault appears more often when the drivetrain is warm

Repair estimate

DifficultyShop_onlyWorkshop job

Parts and labour€150–2,500

Time1.5–6 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.