P0EF8 code meaning
Battery Charger A Input Voltage Sensor B Circuit Range/Performance
What P0EF8 means
P0EF8 is set when input voltage sensor B of charger A delivers a value that is electrically valid but wrong for the situation. No manufacturer documents P0EF8 publicly. GM's rationality test for sensor A, P0D3E in its 2019 plug-in hybrid tables, illustrates the idea: while the car moves at 16 km/h or more, when no plug can be connected, the sensor duty ratio must stay between 8 and 12 %; if 60 of 80 samples taken every 25 ms fall outside, the code is stored as Type B. A charger with two input channels can additionally compare them with each other or with the supply voltage reported by the station. Offset drift or a partial fault in the sensing electronics is the likely cause, wiring less so. Charging may stop or continue at reduced power.
P0EF8 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyWorkshop only
- Typical labor0.3 to 4 hours
- Clears after repairAfter a drive cycle
Symptoms of P0EF8
- AC charging interrupted or slower than expected
- Code may set while driving without any charging attempt
- Charging fault message
Common causes of P0EF8
- Most likelyOffset drift of the voltage sensing electronics in the charger
- PossiblePartial internal fault of the charger input stage
- Less likelyCharger software misjudging the plausibility window
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Battery charger a input voltage sensor bOn board charger
What each part of P0EF8 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| F8 | The exact fault in that area. |
What to do next
- Note P0EF8 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 P0EF8
What does P0EF8 mean?
P0EF8 means "Battery Charger A Input Voltage Sensor B Circuit Range/Performance". P0EF8 is set when input voltage sensor B of charger A delivers a value that is electrically valid but wrong for the situation. It is a generic code, so it means the same on every make.
Is it safe to drive with P0EF8?
P0EF8 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will P0EF8 fail an emissions test?
P0EF8 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is P0EF8 to fix?
Difficulty: workshop only. A typical repair takes 0.3 to 4 hours of work. This is a job for a workshop.
Will P0EF8 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.