P0CD7: Hybrid/EV Battery Pack Coolant Temperature Sensor B Circuit Low

P0CD7 reports that the signal of battery coolant temperature sensor B at the pack outlet has dropped toward ground. On an NTC thermistor with pull-up resistor a low voltage reads as very hot coolant, so a short to ground or a damaged sensor is the usual explanation rather than real overheating. GM's battery energy control module in the 2011 Chevrolet Volt and 2016 Cadillac ELR stores the code once the outlet value reaches 87.9 °C, an ADC count of 130 or less, for 1.75 s within a 2.5 s window; it is rated Type B, so the MIL lights after the second trip. While it is active, GM suspends the outlet plausibility test P0CD6 and the coolant pump checks that rely on this value. Expect reduced charging or power until the signal is back. The open-circuit counterpart is P0CD8, sensor A low is P0C44.

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 after two trips (GM)
Displayed outlet coolant temperature implausibly high
Charging or drive power reduced

Most likely causes

Signal wire of sensor B shorted to ground
Sensor B internally shorted or water-damaged
Input stage of 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
With the connector unplugged, check whether the signal wire is making contact with ground.
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 P0CD7 means

P: Powertrain: engine and transmission
0: Generic code: same on every make
C: Subsystem depends on the code range
D7: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0CD7?

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 P0CD7?

The most common causes are: signal wire of sensor B shorted to ground; sensor B internally shorted or water-damaged; input stage of 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.