P0EC8A/C Power Supply Relay Control Circuit High
- Generic OBD-II code · Powertrain
- How the car detects it
- P0EC8 indicates that the relay control circuit for the A/C power supply carries too high a voltage, typically a short to a battery-fed wire. A low-side driver then pushes current straight into that short when it switches on; modern output stages detect the overcurrent, turn themselves off and log this code, so the relay stays open and the A/C components get no power. With a high-side driver the same fault can hold the relay on permanently. No manufacturer documents P0EC8 publicly. CARB explicitly lists shorts toward a higher voltage as a circuit fault that output component monitoring must catch. Look for wires rubbing on a powered conductor or a shorted coil. Low side: P0EC7; clutch relay analogue: P0647.
- What you may notice
- A/C has no power and stays off
- Relay may stay energised permanently on high-side switched designs
- Likely causes
- LikelyControl line shorted to a battery-fed wire
- PossibleRelay coil with too low resistance overloading the driver
- RareIncorrect relay type fitted
- Repair
- Medium · Usually a job for a workshop.Typical cost: €20 – €350
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.