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.

Likely causes

Symptoms

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

Repair estimate

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

Related codes

References: law.cornell.edu, gsi.ext.gm.com.