Powertrain, generic · Hybrid propulsion

P0C50 Drive Motor A Position Sensor Circuit A

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

A resolver has two pickup windings set 90 degrees apart, one giving a sine and one a cosine signal. The codes P0C50 onward judge each of those circuits on its own, while P0A3F to P0A43 judge the combined angle signal. GM names the S1/S3 winding Circuit A and the S2/S4 winding Circuit B. P0C50 is the general entry for Circuit A of motor A, used when the controller sees a fault in that line without classing it as a low or high reading. No manufacturer documents this code publicly; GM covers the same winding only through P0C52 and P0C53. CARB requires circuit faults of such inputs to be detected and stored separately from out-of-range faults. Expect a warning lamp and possibly lost electric drive.

Likely causes

Open wire or loose terminal in the Circuit A (first pickup winding) lines
Corroded or damaged connector between resolver and motor control module
Defective pickup winding inside the resolver stator
Fault in the resolver input stage of the motor control module

Symptoms

  • Hybrid or drive system warning together with the check engine lamp
  • Electric drive switched off or reduced power
  • Vehicle may not reach ready mode

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 awiring harnesshybrid control module

Related codes

P0C51P0C52P0C53P0C54P0C5AP0A3F

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