P0645 on Nissan: How to Diagnose & Fix
A/C Clutch Relay Control Circuit
1 Nissan model · 1 documented issue · $250-$1,300 repair
P0645 on Nissan by model: symptoms, diagnosis and fix
The Murano A/C compressor clutch is prone to failure, particularly on the first and second generation models. The clutch relay, clutch coil, or the compressor clutch bearing can fail, resulting in no A/C cooling. Symptoms often start with intermittent A/C operation — cooling works sometimes but not others — before progressing to complete failure. A seized compressor clutch bearing will produce a constant squealing noise with the A/C off.
Common Symptoms
- A/C blows warm air intermittently
- A/C stops cooling completely
- Squealing noise from engine bay
- A/C clutch not engaging
- Burning rubber smell with A/C on
How to Fix
If only the clutch coil has failed, it can be replaced separately ($100-200 parts + $150-250 labor). If the clutch bearing is seized, the compressor assembly typically needs replacement ($400-800 for aftermarket compressor, $300-500 labor). The system needs to be evacuated and recharged ($100-150). Replace the receiver drier when replacing the compressor.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Nissan 2003-2007 Murano A/C compressor clutch 92660-CA01C
Confirm VIN and non-returnability.
- Genuine Nissan 2008-2014 Murano A/C compressor clutch 92660-JP00B
Confirm VIN and installed compressor.
- Genuine Nissan Value Advantage 2003-2006 Murano A/C compressor K2600-CA01C
Confirm VIN and K2600-CA01C supersession.
- Genuine Nissan 2008-2014 Murano A/C compressor 92600-JP01C
Confirm VIN, oil charge and refrigerant-system procedure.
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Sources for this issue (2)
P0645 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0645 mean on a Nissan?
P0645 stands for "A/C Clutch Relay Control Circuit." A general fault in the A/C compressor clutch relay control circuit driven by the control module. The commanded relay state does not match the measured circuit condition. On Nissan it is documented across 1 model: Murano.
What are the most common causes of P0645?
The most common causes of P0645 are: Faulty A/C clutch relay, Open or short in the relay control circuit, Corroded/damaged connectors, Blown fuse, Internal PCM driver fault. The specific cause varies by vehicle.
How much does it cost to fix P0645 on a Nissan?
Published repair estimates on Nissan range from $250 to $1,300 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.