Powertrain, generic

P0EC6 A/C Power Supply Relay Control Circuit/Open

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

P0EC6 concerns the control side of the relay that switches power to air conditioning components, typically the compressor or climate electronics. The module driving the relay coil notices that its output does not behave as commanded, most often because the coil circuit is open. No manufacturer documents P0EC6 publicly, and the exact wiring differs by maker. CARB requires output components to be checked either functionally or for circuit continuity and shorts, and lets manufacturers report open and shorted states under one code, which is the role of this umbrella code. A relay that never pulls in leaves the A/C without power. Voltage-specific faults: P0EC7 and P0EC8; the clutch relay equivalent is P0645.

Likely causes

Relay coil burnt open or relay missing
Open control wire or loose relay socket terminal
Failed output driver in the controlling module

Symptoms

  • A/C or electric compressor completely without function
  • No relay click when A/C is requested

Repair estimate

DifficultyMediumDIY possible
Parts and labour€20–300
Time0.3–1.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

ac power supply relayhvac control modulewiring harness

Related codes

P0EC7P0EC8P0645

References: law.cornell.edu, mitsubishitechinfo.com.