P0CBD: Drive Motor A Coolant Temperature Sensor Circuit Range/Performance

What does P0CBD mean?

P0CBD reports that the coolant temperature sensor of drive motor A gives a believable voltage but an implausible temperature. GM uses it on the 2013 eAssist models, where the drive motor is the belt-driven motor generator with its own small cooling loop. Table 13OBDG05C runs the check once per key cycle after an engine-off period of more than 21,600 s: the loop sensor is compared with the mean of stator temperature, intake air temperature and transmission fluid temperature, and a difference above 25 °C in 50 of 62 samples at 100 ms is a Type B fault. The test is skipped while stator sensor codes P0A2B–P0A2D, intake air or transmission fluid sensor codes, the sensor's own P0CBE/P0CBF or CAN faults U0100/U0101 are active. A drifting sensor is the likely cause; the motor generator may be limited meanwhile.

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

Symptoms

• Check-engine lamp after the second faulty trip
• Reduced electric assist or regeneration

Common causes

• High Coolant temperature sensor drifted out of its curve
• Medium Added resistance from a corroded connector
• Low One of the comparison sensors (stator, intake air, transmission oil) reading wrongly

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