P0C3BDC/DC Converter Temperature Sensor A High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P0C3B reports a signal from DC/DC converter temperature sensor A above its valid range, typically a short to positive or an open circuit pulled up by the input. Mercedes-Benz documents it on series 243 (EQB) and 465 (G-Class, including the electric G 580): information LI54.10-P-079533 describes P0C3B00 as a short circuit to positive of temperature sensor A, stored together with P0E9700, P0E5400 and P0C4000 after faulty wake-up behaviour of the converter. Drivers see a red 12 V battery message and white or yellow HV warnings. The remedy is a converter check in XENTRY, clearing the fault memory and a converter reset; parts are not replaced first. The low-signal sibling is P0C3A, sensor B's high code is P0C40.
- What you may notice
- Red 12 V battery warning in the cluster
- White or yellow high-voltage system warning
- 12 V battery no longer charged while driving
- Likely causes
- LikelyFaulty wake-up behaviour of the converter putting it into an error state (Mercedes 243/465)
- PossibleOpen circuit or short to positive in the sensor A circuit
- RareInternal defect of the DC/DC converter
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €80 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.