Powertrain, generic · Hybrid propulsion

P0C57 Drive Motor B Position Sensor Circuit A Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0C57 means the reference level on Circuit A of the motor B resolver, the S1/S3 winding in GM wiring, has sunk below its limit. GM checks it exactly like the motor A line: under 0.5 V on the 2011 and 2016 Volt and the 2012 two-mode trucks, under 0.10 V on the 2019 Volt, with Type A on the early cars and Type B from 2016. In the field it rarely stands alone. GM preliminary information PIC5856A to F for 2011-13 Volt and 2014-16 ELR groups P0C57 with P0C58 and P0C62: if wiring checks and normal diagnosis find nothing, the motor B position sensor is replaced and the drive motor generator control module is brought to its latest calibration. A genuine harness fault to ground still has to be excluded before any parts are ordered.

Likely causes

Faulty motor B position sensor (resolver stator) on Volt and ELR (GM PIC5856)
Circuit A line of motor B shorted to ground in the harness
Drive motor generator control module not on the latest calibration

Symptoms

  • Service engine soon lamp, current or in history
  • Often stored together with P0C58 and P0C62
  • Reduced propulsion

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€100–2,500
Time1–8 h

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

Parts involved

drive motor b position sensor awiring harnesshybrid control module

Related codes

P0C58P0C62P0C55P0C61P0A47

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com, static.nhtsa.gov.