P0E34DC/DC Converter Voltage Sensor A High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- With P0E34 the controller sees a voltage on sensor A of the DC/DC converter that is too high to be real, which points to the signal being shorted to a battery feed or another live wire. In GM's 2025 tables (25OBDG03A) the ECM flags it when raw voltage value 1 exceeds 28 V, far above anything a 12 V converter output should reach. Sampling and confirmation mirror the low case: 320 of 400 readings must fail, battery voltage must be 6.6 V or more, and as a Type B fault it needs two trips before the MIL lights. A real overvoltage of the converter would not normally reach that value, so the wiring and the sensing path come first. Low readings on the same sensor use P0E33; sensor B has P0E39 for the same fault.
- What you may notice
- MIL on after two trips (GM)
- Engine auto-stop disabled
- Likely causes
- LikelySignal wire shorted to a battery feed or other live circuit
- PossibleLost reference ground of the measurement, signal floats high
- RareFaulty measuring circuit in the converter
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €80 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.