Powertrain, generic

P0E16 Hybrid/EV Battery Pack Coolant Heater B Control Circuit/Open

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0E16 is the open-circuit code for a second battery coolant heater, B. Why a car has two: some thermal systems pair the pack heater with another heater, for example one for the cabin loop, and can route its heat to the battery. A patent from Magna E-Car describes exactly that fallback when the battery pack heater fails, so the letter depends on how the maker splits the heaters. No manufacturer documents P0E16 publicly, and none of the GM, Ford or Stellantis papers checked used it. The logic matches heater A, which GM's 2016 Volt checks as P1EC3 with 20 failures in 40 samples (Type B). CARB requires circuit monitoring of each output used to heat the energy store. Look for a broken wire, a loose connector or an open element. P0E17 and P0E18 are the shorts.

Likely causes

Broken wire in the heater B command circuit
Loose or corroded connector at heater B
Open element or electronics inside heater B

Symptoms

  • Check engine light on
  • Battery warms up slowly in cold weather
  • Reduced charging power at low temperatures

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

P0E17P0E18P0E19P0E12

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