P0E33DC/DC Converter Voltage Sensor A Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P0E33 means the controller reads an implausibly low value from voltage sensor A of a DC/DC converter, typically because the signal wire is shorted to ground. GM documents it in its 2025 engine control tables (25OBDG03A) for a converter that keeps the 12 V network stable while the engine restarts automatically: the raw voltage value 1 must drop below 1 V, and 320 failing samples out of 400 taken every 12.5 ms, about four seconds, are needed. The test runs with at least 6.6 V battery voltage in run/crank or accessory mode. GM rates it Type B, so the MIL comes on after two trips. P0E34 is the opposite case on the same sensor, P0E38 the matching fault on sensor B. Start-stop and the 12 V support can be limited.
- What you may notice
- MIL on after two trips (GM)
- Auto stop/start no longer available
- Possible 12 V voltage dips during engine restarts
- Likely causes
- LikelySensor signal wire chafed through to ground
- PossibleVoltage measurement inside the converter failed
- RareMoisture in the converter connector bridging to ground
- 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.