Engine-Codes.com
Engine-Codes – GMC – P0646 2014 GMC Sierra

P0646 2014 GMC Sierra Code - Air Conditioning Compressor Clutch Relay Control Circuit Low Voltage

Quick Answer

The P0646 diagnostic trouble code (DTC) specifically pertains to the air conditioning compressor clutch relay control circuit in a 2014 GMC Sierra. Common causes include Faulty air conditioning compressor clutch relay, Wiring issues or electrical connections related to the compressor clutch relay circuit, Defective compressor clutch. Severity is Low - monitor the vehicle and repair when practical. The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.

What it means
P0646 2014 GMC Sierra indicates Air Conditioning Compressor Clutch Relay Control Circuit Low Voltage.
Common causes
Common causes include Faulty air conditioning compressor clutch relay, Wiring issues or electrical connections related to the compressor clutch relay circuit, Defective compressor clutch.
Severity
Low - monitor the vehicle and repair when practical.
Can I drive?
The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.
What is this?
Table of contents Created and updated by William Orellana on Sep 11, 2024
💬 Need more help? Ask Auto Expert for instant answers — it's free!
AutoCodes App

Fix Your Car Smarter

Try the New AutoCodes App!

Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.

AutoCodes App on Google Play

Code P0646 2014 GMC Sierra Description

The P0646 diagnostic trouble code (DTC) specifically pertains to the air conditioning compressor clutch relay control circuit in a 2014 GMC Sierra. This code indicates that the voltage in the control circuit for the air conditioning compressor clutch relay is below the expected range. The air conditioning compressor clutch relay is responsible for engaging and disengaging the compressor clutch in the air conditioning system, which regulates the flow of refrigerant and ultimately controls the cooling function of the vehicle's AC system.

OBDII Code P0646 2014 GMC Sierra - Air Conditioning Compressor Clutch Relay Control Circuit Low Voltage
P0646 2014 GMC Sierra Code - Air Conditioning Compressor Clutch Relay Control Circuit Low Voltage

Common Causes of P0646 2014 GMC Sierra

  1. Faulty air conditioning compressor clutch relay
  2. Wiring issues or electrical connections related to the compressor clutch relay circuit
  3. Defective compressor clutch
  4. Electrical system issues within the vehicle
  5. Environmental factors such as moisture or corrosion affecting the relay control circuit

Symptoms of P0646 2014 GMC Sierra

  1. Lack of cool air coming from the air conditioning system
  2. Air conditioning system not engaging or turning on
  3. Unusual noises coming from the air conditioning compressor
  4. Inconsistent cooling performance when the AC is turned on
  5. Dashboard warning light illuminated indicating a fault with the AC system

How to Fix P0646 2014 GMC Sierra

  1. Begin by conducting a thorough inspection of the air conditioning compressor clutch relay and its control circuit.
  2. Test the relay using a multimeter to determine if it is functioning correctly or if it needs to be replaced.
  3. Check for any loose or damaged wiring connections in the relay control circuit and repair or replace as necessary.
  4. Inspect the compressor clutch for any signs of damage or wear and replace if needed.
  5. Clear the DTC from the vehicle's system and test the air conditioning system to ensure proper functionality after the repairs have been completed.

Cost to Fix P0646 2014 GMC Sierra

The typical repair costs for addressing a P0646 code related to the air conditioning compressor clutch relay control circuit in a 2014 GMC Sierra can range from $150 to $500, including parts and labor. However, it is essential to note that specific diagnosis time and labor rates at auto repair shops can vary significantly based on factors such as location, vehicle make and model, and engine type. It is recommended to check with local auto repair shops for a more accurate estimate based on individual circumstances.

Need more information about the P0646 2014 GMC Sierra code?

Need more information on how to fix the P0646 2014 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0646 2014 GMC Sierra 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 P0646 2014 GMC Sierra Code

1. What does OBDII code P0646 mean on a 2014 GMC Sierra?

Code P0646 indicates a low voltage issue in the Air Conditioning (A/C) Compressor Clutch Relay Control Circuit, which affects the operation of the A/C system.

2. What are the common symptoms of P0646 in a 2014 GMC Sierra?

Symptoms include the A/C not blowing cold air, the A/C compressor not engaging, an illuminated Check Engine Light, and possibly reduced fuel efficiency if the system is not functioning properly.

3. What causes code P0646 in a 2014 GMC Sierra?

Common causes include a faulty A/C compressor clutch relay, damaged wiring or connectors in the control circuit, a blown fuse, or a problem with the Powertrain Control Module (PCM).

4. Can I drive my 2014 GMC Sierra with a P0646 code?

Yes, the vehicle is safe to drive, but the air conditioning system may not function correctly. Prolonged use without addressing the issue could lead to further electrical problems.

5. How do I diagnose the P0646 code on a 2014 GMC Sierra?

Start by inspecting the A/C compressor clutch relay, related fuses, and wiring for damage or corrosion. Use a multimeter to check for proper voltage and continuity in the circuit.

6. How do I fix a P0646 code on a 2014 GMC Sierra?

Repairs might include replacing the A/C compressor clutch relay, repairing damaged wiring or connectors, replacing a blown fuse, or reprogramming or replacing the PCM if necessary.

7. How much does it cost to fix a P0646 code on a 2014 GMC Sierra?

Repair costs vary depending on the issue. Replacing a relay or fuse might cost $50-$150, while addressing wiring or PCM issues could range from $200 to $1,000.

8. Can a bad battery cause the P0646 code in a 2014 GMC Sierra?

Yes, a weak or failing battery can cause electrical issues, including low voltage in the A/C compressor clutch relay control circuit.

9. Does clearing the P0646 code fix the problem on a 2014 GMC Sierra?

Clearing the code will reset the Check Engine Light temporarily, but the underlying issue must be resolved to prevent the code from returning.

10. What tools are needed to troubleshoot a P0646 code on a 2014 GMC Sierra?

You’ll need an OBDII scanner, a multimeter, basic hand tools, and possibly a wiring diagram for the A/C compressor clutch relay circuit.

Discuss the causes and fixes for P0646 2014 GMC Sierra OBDII Code

Submit a New Comment

Code P0646 2014 GMC Sierra comments

No comments found for this page.