P0646 2017 Chevrolet Silverado Code - Air Conditioning Compressor Clutch Relay Control Circuit Low 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
- P0646 2017 Chevrolet Silverado indicates Air Conditioning Compressor Clutch Relay Control Circuit Low 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.
Code P0646 2017 Chevrolet Silverado Description
What are the Possible Causes of the DTC P0646 2017 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 P0646 2017 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 P0646 2017 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 P0646 2017 Chevrolet Silverado code?
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Frequently Asked Questions about P0646 2017 Chevrolet Silverado Code
1. What does the OBDII code P0646 mean on a 2017 Chevrolet Silverado?
P0646 indicates a low voltage issue in the Air Conditioning (A/C) Compressor Clutch Relay Control Circuit, which impacts the operation of the A/C system.
2. What are the common symptoms of a P0646 code in a 2017 Chevy Silverado?
Symptoms include the A/C system not cooling properly, the A/C compressor not engaging, and possibly an illuminated check engine light.
3. What causes the P0646 code in a 2017 Chevrolet Silverado?
Common causes include a faulty A/C compressor clutch relay, damaged wiring or connectors in the control circuit, or a malfunctioning A/C control module.
4. How do I diagnose the P0646 code on my Silverado?
Start by inspecting the A/C compressor clutch relay and its wiring for damage or corrosion. Use a multimeter to check for proper voltage and continuity in the circuit.
5. Can a bad relay cause the P0646 code in a 2017 Silverado?
Yes, a faulty or failed A/C compressor clutch relay is a common cause of the P0646 code.
6. Is it safe to drive my 2017 Chevy Silverado with the P0646 code?
Yes, it’s generally safe to drive, but the A/C system may not function, which could be an issue in hot weather.
7. How can I fix the P0646 code on my Silverado?
Repairs may include replacing the A/C compressor clutch relay, repairing damaged wiring or connectors, or replacing the A/C control module if necessary.
8. How much does it cost to fix a P0646 code in a 2017 Chevrolet Silverado?
Repair costs vary but can range from $50 for a simple relay replacement to $500 or more if the A/C control module needs replacement.
9. Can low refrigerant levels cause the P0646 code?
While low refrigerant levels don’t directly cause the code, they can lead to A/C system issues that may indirectly contribute to circuit problems.
10. Do I need professional help to fix the P0646 code in my Silverado?
You can perform basic checks like inspecting the relay and wiring yourself, but complex electrical diagnostics may require a professional technician.
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