P0CD5: Hybrid/EV Battery Pack Coolant Temperature Sensor B Circuit

P0CD5 is the general circuit fault for the second coolant temperature sensor in the liquid loop of a hybrid or EV battery. In GM's tables for the Chevrolet Volt and Cadillac ELR, sensor B is the one at the pack outlet, an NTC thermistor read by the battery energy control module, while sensor A sits at the inlet. GM splits electrical faults of sensor B into P0CD7 and P0CD8 and does not list P0CD5 itself. No manufacturer publicly documents this general code; it suits controllers that only recognise an unusable signal without telling low from high. CARB requires battery thermal management inputs to be checked for circuit faults. Without the outlet value the controller no longer knows how much the coolant warms across the pack and may limit charging or drive power. Implausible readings fall under P0CD6.

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

Check engine or hybrid system warning lamp
Reduced charging or drive power, especially in heat or cold
Battery heating or cooling runs on substitute values

Most likely causes

Loose, corroded or unplugged connector or damaged wire at the outlet sensor
Coolant temperature sensor B defective
Input circuit or reference in the battery control module faulty

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
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 can trigger limp mode.
It affects emissions.

What each character of P0CD5 means

P: Powertrain: engine and transmission
0: Generic code: same on every make
C: Subsystem depends on the code range
D5: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0CD5?

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 P0CD5?

The most common causes are: loose, corroded or unplugged connector or damaged wire at the outlet sensor; coolant temperature sensor B defective; input circuit or reference in the battery control module faulty.

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.