P0AE4 code meaning
Hybrid/EV Battery Precharge Contactor A Control Circuit/Open
Powertrain system Generic code P0Axx codes Check engine light
What P0AE4 means
P0AE4 concerns the circuit that drives the coil of precharge contactor A, not its contacts. GM uses it in many hybrid and EV tables, with changing logic: the 2016 and 2019 OBDG02 tables look for an open high-side driver circuit, a control voltage between 1.15 and 2.81 V while commanded off, 40 of 50 samples at 12.5 ms, Type B, two trips. The 2019 OBDG01 version also catches a short to power while off and a coil current below 194 mA while on. The 2011 Volt table instead flags a short to battery voltage in the off state, Type A, one trip. With the coil not driven, precharge cannot start and the high-voltage system stays off. Low and high variants are P0AE6 and P0AE7.
P0AE4 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor1 to 5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0AE4
- Vehicle does not become ready to drive
- MIL and hybrid or EV warning on
- Charging not possible
Common causes of P0AE4
- Most likelyOpen control wire or loose connector at the contactor coil
- PossiblePrecharge contactor coil open internally
- Less likelyControl wire shorted to 12 V (GM 2011 and 2019 logic)
- Less likelyDriver stage in the battery or hybrid controller defective
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Hv battery precharge contactor aWiring harnessBms
What each part of P0AE4 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| A | Area: hybrid propulsion. |
| E4 | The exact fault in that area. |
What to do next
- Note P0AE4 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 P0AE4
What does P0AE4 mean?
P0AE4 means "Hybrid/EV Battery Precharge Contactor A Control Circuit/Open". P0AE4 concerns the circuit that drives the coil of precharge contactor A, not its contacts. It is a generic code, so it means the same on every make.
Is it safe to drive with P0AE4?
Drive gently and only to a workshop. With P0AE4 the car can go into limp mode (reduced power) to protect itself.
Will P0AE4 fail an emissions test?
Yes, it can. P0AE4 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 P0AE4 to fix?
Difficulty: workshop only. A typical repair takes 1 to 5 hours of work. This is a job for a workshop.
Will P0AE4 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.