P0C41: DC/DC Converter Temperature Sensor B Intermittent/Erratic

P0C41 concerns a reading from DC/DC converter temperature sensor B that jumps or briefly drops out while it mostly remains inside the valid range. A converter heat sink changes temperature slowly, so abrupt steps indicate a signal problem rather than real heating. No manufacturer documents P0C41 publicly. GM's 2019 hybrid tables show the usual method on the battery coolant thermistor: the controller adds the absolute differences of ten consecutive 100 ms samples and counts a failure when the sum exceeds 64 °C, setting the code after 4 s within a 5 s window. CARB requires hybrid component inputs to be monitored for such faults. Typical culprits are a loose terminal, moisture or vibration damage. Unlike P0C3F and P0C40, the fault can disappear between checks.

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 or EV warning that comes and goes
Short interruptions of 12 V charging

Most likely causes

Loose terminal or moisture at the converter connector
Harness chafed or cracked by vibration
Intermittent contact inside the converter

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 P0C41 means

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

Frequently asked questions

Can I keep driving with code P0C41?

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 P0C41?

The most common causes are: loose terminal or moisture at the converter connector; harness chafed or cracked by vibration; intermittent contact inside the converter.

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.