Powertrain, generic · Hybrid propulsion

P0C88 Hybrid/EV Battery Temperature Sensor I Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P0C88 is the general circuit code for battery temperature sensor I, chosen when the fault is electrical but not classified as low, high or erratic. No manufacturer documents P0C88 publicly. In GM's Volt pack sensor I is the ninth and last thermistor (bulletin 18-NA-342); the 2012 Volt table 12OBDG01A and GM's later tables cover it only through the specific codes P0C89 to P0C8C. Packs with more sensors, such as Mitsubishi's Outlander PHEV with 50, carry the letter as channel [08]. CARB section (e)(15.3.1) requires continuous range and continuity checks on such inputs. With channel I unreliable, the battery controller falls back to cautious power limits. Older code lists show this number as reserved, so some scan tools may not name it.

Likely causes

Connector fault on the sensor I circuit
Thermistor I failed
Defective input channel in the battery sensing electronics

Symptoms

  • Hybrid or EV warning lamp
  • Reduced electric power
  • Generic scan tools may show the code without a description

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€150–2,500
Time1–5 h

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

Parts involved

hv battery temp sensor iwiring harnessbms

Related codes

P0C89P0C8AP0C8BP0C8CP0C81P0C8D

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