P0E39 code meaning
DC/DC Converter Voltage Sensor B High
Powertrain system Generic code P0Exx codes Check engine light
What P0E39 means
P0E39 reports that sensor B of the DC/DC converter reads far too high, a pattern GM attributes to a short to battery. The 2025 engine tables (25OBDG03A) set the bar at more than 28 V for raw voltage value 2, again needing 320 failing samples within 400 at 12.5 ms and a battery voltage of at least 6.6 V, with Type B confirmation over two trips. If only sensor B shows the excess while sensor A and the ECM's own run/crank reading stay normal, a wiring fault on the B path is far more likely than a converter that really puts out such a voltage. A lost reference ground can also let the signal float upward. Sensor A's high code is P0E34; a low reading on sensor B is P0E38, an implausible but valid one P0E37.
P0E39 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyHard
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0E39
- MIL on after two trips (GM)
- Start-stop switched off
Common causes of P0E39
- Most likelySensor B signal shorted to a voltage-carrying wire
- PossibleOpen reference ground letting the signal float high
- Less likelyFailed measuring circuit for sensor B
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Dcdc voltage sensor bWiring harnessDcdc converter
What each part of P0E39 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 39 | The exact fault in that area. |
What to do next
- Note P0E39 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0E39
What does P0E39 mean?
P0E39 means "DC/DC Converter Voltage Sensor B High". P0E39 reports that sensor B of the DC/DC converter reads far too high, a pattern GM attributes to a short to battery. It is a generic code, so it means the same on every make.
Is it safe to drive with P0E39?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P0E39 fail an emissions test?
Yes, it can. P0E39 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0E39 to fix?
Difficulty: hard. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will P0E39 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.