Powertrain, generic

P0E17 Hybrid/EV Battery Pack Coolant Heater B Control Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0E17 reports that the command signal to battery coolant heater B stays too low, most often from a short to ground between controller and heater. No manufacturer documents P0E17 publicly. Some designs give the second heater a different job, such as warming the cabin loop, and only borrow it for the pack when needed, as a Magna E-Car patent outlines; the wiring of heater B may then run through other areas than that of heater A. GM covers ground shorts of its battery heater command inside the broader code P1EC3 on the 2016 Volt (Type B), so an exact low-only threshold is not public. CARB requires circuit checks on heating outputs of the energy store. Chafing near brackets and water in the plug are the classic finds. Open circuit is P0E16, short to voltage P0E18.

Likely causes

Heater B command wire shorted to ground
Water or coolant in the heater B connector
Internal short at the control input of heater B

Symptoms

  • Check engine light on
  • Second heater does not support battery warm-up
  • Slower charging in winter

Repair estimate

DifficultyHardWorkshop job
Parts and labour€80–1,500
Time1–4 h

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

Parts involved

hv battery pack coolant heater bwiring harnessbms

Related codes

P0E16P0E18P0E19P0E13

References: patents.google.com, gsi.ext.gm.com, law.cornell.edu.