P0646

2017-10-10

Description:

  • The fault code P0646 indicates that there is an issue with the A/C clutch relay control circuit, which is operating at lower than the normal voltage levels. This may cause the A/C to stop working or work intermittently.

Possible Symptoms:

  • A/C may not work or may work intermittently

  • Illuminated A/C light on the dashboard

  • Reduced fuel efficiency

  • Illuminated check engine light

Possible Causes:

  • Faulty A/C clutch relay

  • Wiring or connections in the circuit that are damaged or corroded

  • Loose or corroded electrical connections

  • Failed engine control module (ECM)

Related Parts:

  • AC Clutch Relay: The A/C clutch runs the A/C compressor. Problems lead to reduced or no AC cooling

Possible Solutions:

  • Replace the A/C clutch relay

  • Check and repair any damaged wiring or connections

  • Tighten or clean any loose or corroded electrical connections

  • Replace the engine control module (ECM) if necessary

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