P0C77 code meaning
Hybrid/EV Battery System Precharge Time Too Short
Powertrain system Generic code P0Cxx codes Check engine light
What P0C77 means
P0C77 is stored when the inverter side reaches battery voltage too quickly during precharge. Before the main contactor closes, the controller charges the inverter capacitor through a precharge resistor and watches the ratio of bus to battery voltage. GM's 2011 Volt sets the code if that ratio passes 95 % within 50 ms of precharge start, Type A; the 2013 eAssist uses 75 ms, Type B, and both require the bus to be below 40 V beforehand. A rise that fast suggests a bypassed or shorted resistor, a main contactor that is welded or closes early, or far less capacitance on the bus than expected. Chrysler lists P0C77 for the 2017 Pacifica Hybrid together with a high-voltage cable that had worked loose on the inverter terminal (08-107-17). Propulsion may be unavailable.
P0C77 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor0.5 to 5 hours
- Clears after repairAfter a drive cycle
Symptoms of P0C77
- Malfunction indicator or hybrid warning lamp
- Vehicle does not become ready or loses propulsion
Common causes of P0C77
- PossibleMain contactor welded or closing before precharge ends
- PossiblePrecharge resistor bypassed or shorted
- PossibleLoose high-voltage cable leaving the inverter capacitor partly disconnected
- Less likelyFaulty bus or battery voltage measurement
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Hv battery systemPrecharge resistorMain contactors
What each part of P0C77 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. |
| 77 | The exact fault in that area. |
What to do next
- Note P0C77 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 P0C77
What does P0C77 mean?
P0C77 means "Hybrid/EV Battery System Precharge Time Too Short". P0C77 is stored when the inverter side reaches battery voltage too quickly during precharge. It is a generic code, so it means the same on every make.
Is it safe to drive with P0C77?
Drive gently and only to a workshop. With P0C77 the car can go into limp mode (reduced power) to protect itself.
Will P0C77 fail an emissions test?
Yes, it can. P0C77 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 P0C77 to fix?
Difficulty: workshop only. A typical repair takes 0.5 to 5 hours of work. This is a job for a workshop.
Will P0C77 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.