P0C77Hybrid/EV Battery System Precharge Time Too Short
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- 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.
- What you may notice
- Malfunction indicator or hybrid warning lamp
- Vehicle does not become ready or loses propulsion
- Likely causes
- PossibleMain contactor welded or closing before precharge ends
- PossiblePrecharge resistor bypassed or shorted
- PossibleLoose high-voltage cable leaving the inverter capacitor partly disconnected
- RareFaulty bus or battery voltage measurement
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €100 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.