P0646 2016 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 2016 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 2016 Chevrolet Silverado Description
What are the Possible Causes of the DTC P0646 2016 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 2016 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 2016 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 2016 Chevrolet Silverado code?
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Frequently Asked Questions about P0646 2016 Chevrolet Silverado Code
What does the OBDII code P0646 mean for a 2016 Chevrolet Silverado?
P0646 indicates a problem with the Air Conditioning Compressor Clutch Relay Control Circuit, specifically low voltage detected by the PCM.
What are the symptoms of code P0646 in a 2016 Chevrolet Silverado?
Symptoms may include the air conditioning not working, reduced cooling performance, or the A/C compressor failing to engage.
What causes the P0646 code on the 2016 Chevrolet Silverado?
Common causes include a faulty A/C compressor clutch relay, damaged wiring or connectors in the control circuit, or a malfunctioning PCM.
Can a bad A/C compressor cause the P0646 code?
While uncommon, a failing A/C compressor could indirectly contribute to the code if it causes electrical issues in the clutch relay circuit.
How do I diagnose the P0646 code on a 2016 Chevrolet Silverado?
Start by inspecting the wiring and connectors for damage or corrosion, testing the A/C compressor clutch relay, and checking for proper voltage in the circuit.
Can I drive my 2016 Chevrolet Silverado with the P0646 code?
Yes, the vehicle is typically drivable, but the air conditioning system may not function properly, which can be uncomfortable in hot weather.
How do I fix the P0646 code on a 2016 Chevrolet Silverado?
Repairs may include replacing a faulty A/C compressor clutch relay, repairing damaged wiring, or addressing PCM issues if necessary.
Does the P0646 code always mean the PCM is faulty?
No, PCM failure is rare. Most issues are related to the relay, wiring, or connectors in the control circuit.
How much does it cost to repair a P0646 code on a 2016 Chevrolet Silverado?
Repair costs vary but typically range from $100 to $300, depending on whether parts like the relay or wiring need replacement.
Can a weak battery cause the P0646 code on a 2016 Chevrolet Silverado?
Yes, a weak battery or poor electrical system performance can sometimes lead to low voltage issues and trigger this code.
Discuss the causes and fixes for P0646 2016 Chevrolet Silverado OBDII Code
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