Powertrain, generic · Hybrid propulsion

P0CF2 Hybrid/EV Electronics Coolant Temperature Sensor A Circuit Intermittent/Erratic

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

This code catches a coolant temperature signal that jumps around faster than a liquid can actually change temperature, without necessarily leaving the valid voltage window. GM computes a string length: the controller adds up the absolute steps between four consecutive readings taken 250 ms apart. If that total exceeds 90 °C (2016 Volt, 19OBDG01) or 95 °C (16OBDG02), the window counts as failed; 4 of 5 windows, 5 of 7 windows or 1 s in a 1.25 s window then set the code, Type B, two trips. Loose terminals, a cracked solder joint in the sensor or a chafed wire that touches intermittently produce such spikes. Steady faults are P0CF0/P0CF1, a stable but wrong value P0CEF. The erratic reading can make the pump and power limits react without reason.

Likely causes

Loose or spread terminal in the sensor connector
Chafed wire making intermittent contact with ground or another circuit
Cracked internal connection in the sensor

Symptoms

  • Malfunction indicator lamp, sometimes coming and going
  • Coolant temperature value jumps in live data
  • Pump speed or power limits change without reason

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€30–400
Time0.5–2.5 h

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

Parts involved

hybrid electronics coolant temp sensor awiring harnesshybrid control module

Related codes

P0CEEP0CEFP0CF0P0CF1

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