P0CB8: Hybrid/EV Battery Temperature Sensor P Circuit Range/Performance

What does P0CB8 mean?

P0CB8 flags sensor P as implausible: its value is electrically fine, but after a long rest it disagrees with the temperature of the other modules. GM runs this comparison in the 2012 Volt table 12OBDG01A only when drive system, external charging and battery conditioning have rested for over 21,600 s, so the whole pack should have settled; 50 of 67 samples more than 25.3 °C from the average give a Type B fault. In the HPC2 table 18OBDG02 the limit is 25.00 °C, sampled every 25 ms for about 1.7 s, and the check is held back by circuit or erratic faults and by lost communication. Mitsubishi uses P0CB8 for module sensor [15] of the Outlander PHEV with a 13 °C limit over 0.32 s after more than 3,600 s soak. Comparing all sensors in live data after an overnight stand shows the outlier.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Warning appearing at the first drive after a long stand
• Battery output restricted

Common causes

• High Thermistor P drifted out of calibration
• Medium Sensor P detached from its module surface
• Low Real temperature difference of that module, e.g. faulty cell

Likelihood is a general estimate across vehicles; your make and model may differ.