P0C79 code meaning
Drive Motor A Inverter Voltage Too High
Powertrain system Generic code P0Cxx codes Check engine light
What P0C79 means
P0C79 reports that the DC voltage at the inverter of drive motor A rose above its protection limit. Overvoltage can come from regenerative energy the battery cannot absorb, from a contactor opening under load or a loose high-voltage connection, and it can also be a false reading. In the 2018 Outlander PHEV a hardware comparator in the front motor control unit trips at 370 V; one event with the IGBTs active, or 0.5 s with them shut down, sets the code; after ruling out other voltage codes, the manual checks the torque of the battery cable at the power drive unit. Subaru revised its diagnosis for the 2014-2015 Crosstrek Hybrid (16-114-18), and Audi traces intermittent P0C7900 on the Q4 e-tron to software. Drive motor B uses P0C7A, the generator P0C7B.
P0C79 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor0.5 to 6 hours
- Clears after repairAfter a drive cycle
Symptoms of P0C79
- Hybrid or EV warning lamp, electrical system fault message
- Drive system will not activate or shuts down until restarted
- Reduced drive power
Common causes of P0C79
- PossibleBattery cable at the inverter loose or not at specified torque
- PossibleInverter or its voltage detection faulty
- PossibleVoltage spike from regeneration or a contactor opening under load
- Less likelyMotor control software, fixed by an update
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Drive motor a inverterDc link capacitor
What each part of P0C79 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| C | Area: hybrid propulsion. |
| 79 | The exact fault in that area. |
What to do next
- Note P0C79 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 P0C79
What does P0C79 mean?
P0C79 means "Drive Motor A Inverter Voltage Too High". P0C79 reports that the DC voltage at the inverter of drive motor A rose above its protection limit. It is a generic code, so it means the same on every make.
Is it safe to drive with P0C79?
Drive gently and only to a workshop. With P0C79 the car can go into limp mode (reduced power) to protect itself.
Will P0C79 fail an emissions test?
Yes, it can. P0C79 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 P0C79 to fix?
Difficulty: workshop only. A typical repair takes 0.5 to 6 hours of work. This is a job for a workshop.
Will P0C79 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.