Powertrain, generic · Hybrid propulsion

P0CD8 Hybrid/EV Battery Pack Coolant Temperature Sensor B Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0CD8 is the high-voltage fault of battery coolant temperature sensor B at the pack outlet. On the usual NTC circuit the signal rises to the reference when the loop is broken, so the controller sees an impossible temperature below -40 °C. The battery energy control modules of the 2011 Chevrolet Volt and 2016 Cadillac ELR use exactly this limit, an ADC count above 3823, held for 1.75 s within 2.5 s; the code is Type B with the MIL on the second trip. Connectors left unplugged after work on the battery, corroded pins, a broken wire or a short to a supply line are the common findings, an open sensor element is rarer. Until it is fixed the battery may not be heated or cooled as intended and cold-weather power can be limited. The low counterpart is P0CD7, sensor A high is P0C45.

Likely causes

Connector of sensor B unplugged or not latched after service
Broken signal or ground wire, corroded terminals
Signal wire shorted to a voltage source
Sensor element internally open

Symptoms

  • MIL on after two trips (GM)
  • Outlet coolant temperature shows about -40 °C
  • Limited power or charging in cold weather

Repair estimate

DifficultyHardWorkshop job
Parts and labour€60–400
Time0.5–2.5 h

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

Parts involved

hv battery pack coolant temp sensor bwiring harnessbms

Related codes

P0CD7P0CD5P0CD9P0C45

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