P0CD6: Hybrid/EV Battery Pack Coolant Temperature Sensor B Circuit Range/Performance

P0CD6 means that coolant temperature sensor B at the battery outlet is electrically fine, yet its value does not fit the rest of the thermal system. GM runs the check in the hybrid controller of the Volt with the coolant pump above 20 % and no circuit faults present: if the outlet reading is more than 10 °C away from both the inlet reading and the mean cell temperature (2011 Volt, 80 of 100 samples at 100 ms), or at least 20 °C in the 2016 ELR (32 of 40 samples at 250 ms, pump running for over a minute), the result is a Type B code with the MIL following on the second trip. Volvo lists ECM-P0CD623 on the 2016-17 XC90 T8 as an incorrect entry cured by a total software upgrade (TJ 32193). Otherwise a drifting sensor, contact resistance or trapped air are likely.

High severity. Can I keep driving?If the car still runs, drive as little as possible and go to a specialized repair shop. Do not touch the orange cables: they carry high voltage.

Symptoms

MIL on, often without noticeable driving symptoms
Battery cooling or heating behaves unexpectedly

Most likely causes

Outlet coolant temperature sensor reading off (drift)
Contact resistance at connector or terminals
Air or low coolant in the battery loop after service
Control module software sets the code incorrectly (e.g. Volvo XC90 T8)

What to check, in order

Start with the simplest. You can tick off each step.

Read the codes with a hybrid-compatible scanner and write down the freeze frame data
Compare the reading with other engine data while varying the engine speed.
Make sure the battery cooling air intake is clean
Check the 12 V auxiliary battery, which can also trigger warnings
Leave any high-voltage measurements to a specialized repair shop

Good to know

Repair difficulty: hard
It affects emissions.

What each character of P0CD6 means

P: Powertrain: engine and transmission
0: Generic code: same on every make
C: Subsystem depends on the code range
D6: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0CD6?

If the car still runs, drive as little as possible and go to a specialized repair shop. Do not touch the orange cables: they carry high voltage.

What causes code P0CD6?

The most common causes are: outlet coolant temperature sensor reading off (drift); contact resistance at connector or terminals; air or low coolant in the battery loop after service.

Related codes

Sources

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.