P2E79 code meaning
Hybrid/EV Electronics Coolant Pump C Performance
Powertrain system Generic code P2Exx codes Check engine light
What P2E79 means
P2E79 is the functional verdict on a third pump in the coolant loop of the traction electronics: command and wiring look healthy, yet the pump does not move coolant the way the controller expects. No manufacturer documents P2E79 or says which pump it calls C. GM has published two strategies for its electronics pump: the 2016 ELR sets P0CEA when the spread between power-electronics coolant temperature and charger temperature grows too large once the pump has been on for over 300 s (32 failures in 40, Type B), and the 2019 tables smooth the difference of commanded versus fed-back pump speed (P19FC). A GM patent adds a comparison of measured with expected pump current. Trapped air, blocked passages, a worn impeller or software can be behind it; Stellantis cured a comparable pump B code (P0C74) by a reflash.
P2E79 at a glance
- Check engine lightYes, usually on
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2E79
- Hybrid or EV system warning lamp, possibly MIL
- Drive power or charging rate limited because electronics run warm
- Gurgling or whirring noise from the electronics coolant loop
Common causes of P2E79
- Most likelyAir trapped in the electronics coolant loop after service or a leak
- PossiblePump C worn or impeller fouled, delivering too little flow
- PossibleKinked hose or clogged cooler passages in the loop
- Less likelyControl software misjudging pump function (update available)
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Hybrid electronics coolant pump cPower electronics coolant loop
What each part of P2E79 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 79 | The exact fault in that area. |
What to do next
- Note P2E79 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 P2E79
What does P2E79 mean?
P2E79 means "Hybrid/EV Electronics Coolant Pump C Performance". P2E79 is the functional verdict on a third pump in the coolant loop of the traction electronics: command and wiring look healthy, yet the pump does not move coolant the way the controller expects. It is a generic code, so it means the same on every make.
Is it safe to drive with P2E79?
Drive gently and only to a workshop. With P2E79 the car can go into limp mode (reduced power) to protect itself.
Will P2E79 fail an emissions test?
P2E79 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 P2E79 to fix?
Difficulty: medium. A typical repair takes 0.5 to 4 hours of work. This is a job for a workshop.
Will P2E79 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.