AutoCodes – Generic – P0647

P0647 Code - Air Conditioning Compressor Clutch Relay Control Circuit High Voltage

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 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: P0647 indicates Air Conditioning Compressor Clutch Relay Control Circuit High Voltage.
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: 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.

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Code Popularity 17,825

How popular is this code, among other codes? Low

Repair Importance Level

Low (Monitor) (1 / 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
Comments
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Code P0647 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 voltage at the A/C compressor clutch relay control circuit.

OBDII Code P0647 - Air Conditioning Compressor Clutch Relay Control Circuit High Voltage - AutoCodes.com — P0647 Code - Air Conditioning Compressor Clutch Relay Control Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P0647?

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 P0647?

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 P0647 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 P0647 code?

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Need Help with the Code?

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Information for Specific Makes

P0647 BMW — Air Conditioning Clutch Relay Circuit High
P0647 Buick — Air Conditioning Compressor Clutch Relay Control Circuit High Voltage
P0647 Cadillac — Air Conditioning Compressor Clutch Relay Control Circuit High Voltage
P0647 Chevrolet — Air Conditioning Compressor Clutch Relay Control Circuit High Voltage
P0647 Chrysler — High Voltage Detected At The AC Clutch Relay
P0647 Dodge — High Voltage Detected At The AC Clutch Relay
P0647 GMC — Air Conditioning Compressor Clutch Relay Control Circuit High Voltage
P0647 Hyundai — Air Conditioning Clutch Relay Circuit High
P0647 Jeep — High Voltage Detected At The AC Clutch Relay
P0647 KIA — Air Conditioning Clutch Relay Circuit High
P0647 Mazda — Air Conditioning Clutch Relay Circuit High
P0647 MINI — Air Conditioning Clutch Relay Circuit High
P0647 Suzuki — Air Conditioning Clutch Relay Circuit High

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.