Powertrain, generic · Hybrid propulsion

P0CD7 Hybrid/EV Battery Pack Coolant Temperature Sensor B Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0CD7 reports that the signal of battery coolant temperature sensor B at the pack outlet has dropped toward ground. On an NTC thermistor with pull-up resistor a low voltage reads as very hot coolant, so a short to ground or a damaged sensor is the usual explanation rather than real overheating. GM's battery energy control module in the 2011 Chevrolet Volt and 2016 Cadillac ELR stores the code once the outlet value reaches 87.9 °C, an ADC count of 130 or less, for 1.75 s within a 2.5 s window; it is rated Type B, so the MIL lights after the second trip. While it is active, GM suspends the outlet plausibility test P0CD6 and the coolant pump checks that rely on this value. Expect reduced charging or power until the signal is back. The open-circuit counterpart is P0CD8, sensor A low is P0C44.

Likely causes

Signal wire of sensor B shorted to ground
Sensor B internally shorted or water-damaged
Input stage of the battery control module faulty

Symptoms

  • MIL on after two trips (GM)
  • Displayed outlet coolant temperature implausibly high
  • Charging or drive power reduced

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

P0CD8P0CD5P0CD6P0C44

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