P0ACE: Hybrid/EV Battery Temperature Sensor C Circuit Intermittent/Erratic

P0ACE flags erratic behaviour of battery temperature sensor C, meaning the reading jumps faster than the heavy battery mass could ever warm or cool. In GM's 2016 and 2019 hybrid tables the controller sums the absolute changes of the sensor value across a 10-sample window taken every 100 ms; a sum above 10 fails the window, and 4 failed windows out of 5 store the code as Type B, two trips. This is the same logic GM uses for sensors A and B. The older two-mode and 2013 programs do not list an erratic code for sensor C. Typical culprits are a loose terminal, a partly broken wire or a connector not fully latched after pack service. Several jumping sensors at once point to the sensing board.

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

Hybrid warning light that appears intermittently
Sensor C value jumps in live data
Occasional power limitation

Most likely causes

Loose terminal or unlatched connector at sensor C
Partly broken sensor wire inside the pack
Fault on the battery sensing board affecting several inputs

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
Gently move the wiring with the engine running and watch whether the reading changes.
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

It can trigger limp mode.
It affects emissions.

What each character of P0ACE means

P: Powertrain: engine and transmission
0: Generic code: same on every make
A: Hybrid or air and fuel
CE: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0ACE?

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 P0ACE?

The most common causes are: loose terminal or unlatched connector at sensor C; partly broken sensor wire inside the pack; fault on the battery sensing board affecting several inputs.

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.