P0645 OBD-II: A/C Clutch Relay Control Circuit

P0645 Severity

Moderate

Will P0645 go away on its own?

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.

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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.

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What causes OBD-II fault code P0645?

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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Tuffy Tire & Auto Service Center - Grandview

4.7
(81)
2.39 mi
1524 W 5th Ave
Columbus, OH
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Excite Auto Repair & Towing

4.4
(15)
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3430 Westerville Road
Columbus, OH
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All In Auto Service

4.9
(22)
6.56 mi
5200 Fisher Road
Columbus, OH
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Tuffy Tire & Auto Service - Grove City

4.4
(520)
6.67 mi
2131 Stringtown Rd
Grove City, OH
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Opens 7:30 AM Mon
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What Does P0645 Code Mean?

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.

P0645 Symptoms

  • A/C may not operate

Common Problems That Trigger the P0645 Code

  • A/C compressor failure
  • A/C compressor relay failure
  • Powertrain Control Module (PCM) failure
  • Wiring issue

Common Repairs Needed for the P0645 Code

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