AutoCodes – Chevrolet – P0645 2015 Chevrolet Silverado

P0645 2015 Chevrolet Silverado Code - Air Conditioning Compressor Clutch Relay Control Circuit

Quick Answer

When the Air Conditioning (A/C) switch is pressed, the Heating, Ventilation, and Air Conditioning (HVAC) control module sends an A/C request message to the Engine Control Module (ECM) via serial data. Common causes include Faulty Air Conditioning (A/C) Compressor Clutch Relay, Air Conditioning Compressor Clutch Relay harness is open or shorted, Air Conditioning Compressor Clutch Relay circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P0645 2015 Chevrolet Silverado indicates Air Conditioning Compressor Clutch Relay Control Circuit.
Common causes: Common causes include Faulty Air Conditioning (A/C) Compressor Clutch Relay, Air Conditioning Compressor Clutch Relay harness is open or shorted, Air Conditioning Compressor Clutch Relay circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 384

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jul 17, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code P0645 2015 Chevrolet Silverado Description

When the Air Conditioning (A/C) switch is pressed, the Heating, Ventilation, and Air Conditioning (HVAC) control module sends an A/C request message to the Engine Control Module (ECM) via serial data. The ECM then grounds the A/C compressor clutch relay coil control circuit, closing the relay contacts. The closed relay contacts provide voltage to the compressor clutch causing it to engage. The Diagnostic Trouble Code (DTC) will be set when the ECM detects a short to ground or an open at the A/C compressor clutch relay control circuit.

OBDII Code P0645 2015 Chevrolet Silverado - Air Conditioning Compressor Clutch Relay Control Circuit - AutoCodes.com — P0645 2015 Chevrolet Silverado Code - Air Conditioning Compressor Clutch Relay Control Circuit

What does this mean?

What are the Possible Causes of the DTC P0645 2015 Chevrolet Silverado?

Faulty Air Conditioning (A/C) Compressor Clutch Relay
Air Conditioning Compressor Clutch Relay harness is open or shorted
Air Conditioning Compressor Clutch Relay circuit poor electrical connection
Faulty Air Conditioning Compressor Clutch
Faulty Engine Control Module (ECM)

How to Fix the DTC P0645 2015 Chevrolet Silverado?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0645 2015 Chevrolet Silverado code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0645 2015 Chevrolet Silverado code?

Need more information on how to fix the P0645 2015 Chevrolet Silverado code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0645 2015 Chevrolet Silverado code diagnosed by a professional: Find a repair shop in your area

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0645 2015 Chevrolet Silverado Code

1. What does the OBDII code P0645 mean on a 2015 Chevrolet Silverado?

P0645 indicates a problem with the Air Conditioning (A/C) Compressor Clutch Relay Control Circuit, which can prevent the A/C system from functioning properly.

2. What are the common symptoms of code P0645 in a 2015 Chevrolet Silverado?

Symptoms include the A/C not blowing cold air, the A/C compressor not engaging, and a possible illuminated Check Engine Light.

3. What causes the P0645 code in a 2015 Chevrolet Silverado?

Common causes include a faulty A/C compressor clutch relay, damaged wiring or connectors in the circuit, a malfunctioning A/C compressor clutch, or an issue with the Powertrain Control Module (PCM).

4. How is the P0645 code diagnosed?

A mechanic will inspect the A/C relay, wiring, and connectors for damage, test the relay for proper function, check the A/C compressor clutch operation, and use a scan tool to monitor related circuit data.

5. Can I still drive my 2015 Silverado with the P0645 code active?

Yes, but the A/C system may not work, which could be uncomfortable in hot weather. Additionally, unresolved electrical issues could lead to further problems over time.

6. How do I fix the P0645 code on my 2015 Chevrolet Silverado?

Repairs may involve replacing a faulty A/C compressor clutch relay, repairing or replacing damaged wiring, or addressing any issues with the A/C compressor clutch or PCM.

7. How can I check if the A/C compressor clutch relay is faulty?

You can test the relay with a multimeter or swap it with a similar relay in the fuse box to see if the issue resolves.

8. Can a blown fuse cause the P0645 code?

Yes, a blown fuse in the A/C system circuit could interrupt power to the A/C compressor clutch relay, triggering the code.

9. How much does it cost to repair the P0645 code?

Costs vary depending on the cause, but replacing a faulty relay typically costs $50â€“$100, while more extensive repairs like addressing wiring issues or replacing the compressor clutch may cost several hundred dollars.

10. Can I prevent the P0645 code from occurring in the future?

Regular maintenance, inspecting A/C system wiring for wear, and promptly addressing any A/C performance issues can help prevent this code from appearing.