P0EC7 code meaning
A/C Power Supply Relay Control Circuit Low
What P0EC7 means
P0EC7 is set when the control line of the relay feeding the A/C reads too low a voltage, usually because it is shorted to ground. What the driver feels depends on how the coil is switched: with a low-side driver a grounded line can keep the relay energised even with the A/C off, while with a high-side driver the relay simply cannot be switched on. No manufacturer documents P0EC7 publicly. As a comparison, Mitsubishi monitors a relay-fed supply on its throttle actuator (P0657): with battery voltage above 8.3 V, the switched line must not sit at or below 6.0 V for 0.35 seconds. Open-circuit code: P0EC6; high counterpart: P0EC8; clutch relay analogue: P0646.
P0EC7 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0EC7
- A/C power stays on with A/C switched off, or never switches on
- Possible battery drain while parked if the relay stays energised
Common causes of P0EC7
- Most likelyRelay control line chafed and shorted to ground
- PossibleShorted turns in the relay coil
- Less likelyOutput stage of the module stuck low
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Ac power supply relayHvac control moduleWiring harness
What each part of P0EC7 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| C7 | The exact fault in that area. |
What to do next
- Note P0EC7 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 P0EC7
What does P0EC7 mean?
P0EC7 means "A/C Power Supply Relay Control Circuit Low". P0EC7 is set when the control line of the relay feeding the A/C reads too low a voltage, usually because it is shorted to ground. It is a generic code, so it means the same on every make.
Is it safe to drive with P0EC7?
P0EC7 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will P0EC7 fail an emissions test?
P0EC7 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 P0EC7 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2 hours of work. This is a job for a workshop.
Will P0EC7 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.