Powertrain, generic · Hybrid propulsion

P0C42 Hybrid/EV Battery Pack Coolant Temperature Sensor A Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0C42 is the general circuit code for the first coolant temperature sensor in the liquid loop of a hybrid or EV battery, typically placed at the pack inlet. The battery controller uses it to decide when to pump, heat or chill the coolant. Volvo documents P0C4200 in the battery energy control module of the XC90 T8 plug-in hybrid from model year 2016, as either an intermittent or a permanent entry with a possible check engine lamp; according to technical journal TJ 33546, once the current software is verified the entry is simply erased and no parts are needed. GM reports faults of the same sensor more precisely as P0C44 and P0C45. CARB requires the inputs of the battery thermal management to be monitored. P0C43 covers implausible readings, P0CD5 sensor B.

Likely causes

Battery controller software flagging the circuit wrongly (Volvo XC90 T8)
Corroded or loose connector or damaged wire at the coolant sensor
Failed coolant temperature sensor A

Symptoms

  • Check engine lamp, often without other complaints
  • Battery cooling or heating running on substitute values
  • Reduced charging or drive power in hot or cold weather

Repair estimate

DifficultyHardWorkshop job
Parts and labour€0–400
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 awiring harnessbms

Related codes

P0C43P0C44P0C45P0C46P0CD5

References: static.nhtsa.gov, law.cornell.edu, gsi.ext.gm.com.