P0646 Low-level Air Conditioning Control Circuit (A/C) Clutch Relay Control Circuit

What is the P0646 fault number? What is the description for Air Conditioning (A/C Clutch Relay Controller Low fault)? How do you fix the P0646 fault code What are the causes and symptoms of the P0646 error code?

What is the P0646 Fault code? What does it all mean?

If the powertrain control module (PCM), or any supporting control modules, detects that the voltage signal from A/C clutch relay control circuit is lower than manufacturer specifications, a code P0646 will be set.

The following control modules will also detect the fault and trigger the code:

• – Alternative fuel control module
• – Body control module
• – Anti-lock brake controller module
• – Instrument cluster control module
• – Fuel injection control module
• – Turbo control module
• Anti-theft module
• – Cruise control module
• – Traction control module
• Distance warning control module
• – Climate control module

The A/C compressor clutch controls the pressure of the A/C system. A relay is located on the compressor clutch. This relay activates the compressor and deactivates it. This circuit may be complex depending on vehicle model and application. There may be multiple control modules connected to it. If the PCM, or any other control modules detects a low voltage signal in compressor clutch relay controller circuit, a malfunction code will be generated and the check engine lamp will be turned on. The fault may have to be repeated 8 times for some vehicles in order for the check engine lamp to light.

The P0646 fault code can affect vehicles of all makes and models, including but not limited to Daewoo, Dodge Chrysler, Dodge, Chrysler Jeep, Dodge, Chrysler, Kia Isuzu Hyundai Duramax Jeep, Ford, Chrysler, Dodge, Chrysler, Dodge, Chrysler, Kia Chrysler, Dodge, Chrysler, Kia Chrysler, Dodge, Chrysler, Kia.

What causes the P0646 Fault code?

This code is usually caused by a defective A/C compressor control relay. The A/C relay control circuit can be integrated into most PCMs.

Here are some reasons why P0646 should be set.

• Defective A/C compressor clutch relay
• – Defective A/C compressor clutch
• – Defective air conditioner compressor
• – Corroded, damaged, burned, disconnected, or disconnected wiring and/or connectors to relay
• – Ground wire causing weak electrical signal
• – A fault in the wiring of the CAN bus harness
• Blown fuse
• – PCM defect or related control module

 

What are the symptoms of the P0646 Fault code?

You may experience the following symptoms if your vehicle has the code P0646:

• – Illumination at the check engine lights
• – Direct or flashing the A/C fault lights
• – The air conditioner is not operating properly.
• – Other related fault codes

 

How do I fix the P0646 fault code?

The following repairs may be able to resolve the P0646 fault code:

• – Repair of damaged wires, connectors, or open or short-circuit problems related to the A/C clutch relay control circuit
• – Replacing A/C clutch relay
• – Replacing blown fuse
• – Cleaning corrosion on connectors
• – Repairing poor electricity connections
• – Replacing the clutch on an A/C compressor that is not working properly
• Repairing an air conditioner compressor that is not working properly
• – Repair of damaged wiring or components on the CAN bus
• Troubleshooting PCMs or other control modules

All cables should be thoroughly inspected. Repair or replace any cables that have corroded or burnt. Some models have a lot of relays and fuse because of their complexity. Make sure you check them all.

Conduct continuity testing to ensure the integrity of cables and associated modules. All ground wires should be checked. Unless specified otherwise, the normal resistance of connections should not exceed 0 ohms. If there is no continuity, it could be caused by a problem in the system. Repair it or replace it. If that fails, you can inspect the A/C clutch relay to determine if it needs replacing.

 

How Serious Is the P0646 Fault Code

This code’s severity depends on how attentive you are to your air conditioner. Some drivers don’t use the air conditioner, they simply open the windows. Air conditioning is essential for others. This code is not intended to cause safety problems or dangers for you or your passengers. However, it should be properly diagnosed and fixed.