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P0645 Severity
Once the vehicle's onboard system no longer detects the issue, most codes will disappear on their own. If your vehicle still has this code, however, it should be properly diagnosed to avoid a more serious problem.
For a proper diagnosis, RepairPal Certified shops have the equipment, tools, and expertise.
Moderate severity codes might not threaten the vehicle's safety or functionality immediately, but you should still get it diagnosed within a reasonable time frame to keep your car running well.
The engine control module (PCM) uses a relay to control voltage to the A/C Compressor Clutch. The A/C clutch engages, allowing the Air Conditioning system to operate. When the PCM is unable to control the relay, code P0645 will set.
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OBD-II Code P0645 is defined as a A/C Clutch Relay Control Circuit
The engine control module (PCM) uses a relay to control voltage to the A/C Compressor Clutch. The A/C clutch engages, allowing the Air Conditioning system to operate. When the PCM is unable to control the relay, code P0645 will set.