P0CDB: Drive Motor A Position Sensor Circuit C Range/Performance

What does P0CDB mean?

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.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

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

Common causes

• Medium Winding or terminal of the resolver changing its values when hot
• Medium Resolver shifted on its mount or rotor bearing play
• Low Motor control module software or calibration

Likelihood is a general estimate across vehicles; your make and model may differ.