Powertrain, generic · Hybrid propulsion

P0CD5 Hybrid/EV Battery Pack Coolant Temperature Sensor B Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0CD5 is the general circuit fault for the second coolant temperature sensor in the liquid loop of a hybrid or EV battery. In GM's tables for the Chevrolet Volt and Cadillac ELR, sensor B is the one at the pack outlet, an NTC thermistor read by the battery energy control module, while sensor A sits at the inlet. GM splits electrical faults of sensor B into P0CD7 and P0CD8 and does not list P0CD5 itself. No manufacturer publicly documents this general code; it suits controllers that only recognise an unusable signal without telling low from high. CARB requires battery thermal management inputs to be checked for circuit faults. Without the outlet value the controller no longer knows how much the coolant warms across the pack and may limit charging or drive power. Implausible readings fall under P0CD6.

Likely causes

Loose, corroded or unplugged connector or damaged wire at the outlet sensor
Coolant temperature sensor B defective
Input circuit or reference in the battery control module faulty

Symptoms

  • Check engine or hybrid system warning lamp
  • Reduced charging or drive power, especially in heat or cold
  • Battery heating or cooling runs on substitute values

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

P0CD6P0CD7P0CD8P0CD9P0C42

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