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Engine-Codes – Generic – U18C4

U18C4 Code - Lost Communication With Video Processing Control Module On Low Speed CAN Bus

Quick Answer

The U18C4 diagnostic trouble code (DTC) indicates that the vehicle's onboard computer has lost communication with the Video Processing Control Module on the Low-Speed Controller Area Network (CAN) bus. Common causes include Faulty Video Processing Control Module, Wiring or connection issues between the Video Processing Control Module and other ECUs on the CAN bus, Corrosion or damage to the CAN bus wiring. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
U18C4 indicates Lost Communication With Video Processing Control Module On Low Speed CAN Bus.
Common causes
Common causes include Faulty Video Processing Control Module, Wiring or connection issues between the Video Processing Control Module and other ECUs on the CAN bus, Corrosion or damage to the CAN bus wiring.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
What is this?
Table of contents Created and updated by William Orellana on Sep 11, 2024
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Code U18C4 Description

The U18C4 diagnostic trouble code (DTC) indicates that the vehicle's onboard computer has lost communication with the Video Processing Control Module on the Low-Speed Controller Area Network (CAN) bus. In modern vehicles, the CAN bus is a communication network that allows various electronic control units (ECUs) to communicate with each other. The Video Processing Control Module is responsible for controlling various video-related functions in the vehicle, such as the backup camera, rear-seat entertainment system, or other video displays.

OBDII Code U18C4 - Lost Communication With Video Processing Control Module On Low Speed CAN Bus
U18C4 Code - Lost Communication With Video Processing Control Module On Low Speed CAN Bus

Common Causes of U18C4

  1. Faulty Video Processing Control Module.
  2. Wiring or connection issues between the Video Processing Control Module and other ECUs on the CAN bus.
  3. Corrosion or damage to the CAN bus wiring.
  4. Software issues with the Video Processing Control Module or other ECUs on the network.
  5. Electrical interference or noise disrupting communication on the CAN bus.

Symptoms of U18C4

  1. Backup camera not functioning properly or not displaying any image.
  2. Rear-seat entertainment system not working.
  3. Video displays flickering or showing distorted images.
  4. Warning light on the dashboard related to video systems.
  5. In some cases, the vehicle may go into a "limp mode" to prevent further damage.

How to Fix U18C4

  1. Begin by conducting a thorough visual inspection of the wiring and connections related to the Video Processing Control Module and the CAN bus. Look for any signs of damage, corrosion, or loose connections.
  2. Use a diagnostic scanner to communicate with the Video Processing Control Module and other relevant ECUs on the CAN bus. Check for any stored fault codes and attempt to establish communication with the module.
  3. If communication cannot be established, verify power and ground connections to the Video Processing Control Module. Ensure that the module is receiving the proper voltage and ground signals.
  4. If no issues are found with the wiring or connections, consider replacing the Video Processing Control Module itself. Ensure that the new module is properly programmed and calibrated to work with the vehicle's systems.
  5. After any repairs or replacements are made, clear the DTC and perform a test drive to verify that the issue has been resolved. Ensure that all video-related systems are functioning properly.

Cost to Fix U18C4

The cost of repairing a U18C4 DTC can vary depending on the specific cause of the issue and the vehicle's make and model. In general, the cost of parts for a Video Processing Control Module replacement can range from $200 to $500, with additional costs for labor. The total repair cost, including parts and labor, could range from $300 to $800 or more. However, it's important to note that labor rates at auto repair shops can vary, so it's advisable to check with local shops for a more accurate estimate.

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Code U18C4 Information for Specific Makes

  • U18C4 Buick — Lost Communication With Video Processing Control Module On Low Speed CAN Bus
  • U18C4 Cadillac — Lost Communication With Video Processing Control Module On Low Speed CAN Bus
  • U18C4 Chevrolet — Lost Communication With Video Processing Control Module On Low Speed CAN Bus
  • U18C4 GMC — Lost Communication With Video Processing Control Module On Low Speed CAN Bus
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 U18C4 Code

1. What are common symptoms of OBDII code U18C4?

- Common symptoms include loss of video display, malfunctioning rearview camera, and issues with other video processing functions in the vehicle.

2. What does the U18C4 code indicate?

- The U18C4 code indicates a communication problem between the vehicle's control module and the video processing unit on the low-speed CAN bus.

3. What are some possible causes of the U18C4 code?

- Possible causes include damaged wiring or connectors, a faulty video processing control module, issues with the low-speed CAN bus communication network, or a software malfunction.

4. How can I diagnose the U18C4 code?

- Diagnosing the U18C4 code typically involves using a diagnostic scanner to retrieve the code and checking the connections and wiring related to the video processing control module and the low-speed CAN bus.

5. Is it safe to drive with the U18C4 code present?

- It is generally safe to drive with the U18C4 code, but it is important to address the underlying issue promptly to avoid potential safety risks and further damage to the vehicle's systems.

6. Can I repair the U18C4 code myself?

- Repairing the U18C4 code may require advanced diagnostic tools and knowledge of automotive electronics. It is recommended to consult a qualified mechanic or dealership for proper diagnosis and repair.

7. How much does it cost to fix the U18C4 code?

- The cost of fixing the U18C4 code can vary depending on the underlying cause. It may involve simple repairs such as fixing a loose connection or more complex repairs like replacing the video processing control module.

8. Are there any preventive measures to avoid the U18C4 code?

- Regular maintenance checks, including inspecting wiring and connectors related to the video processing control module, can help prevent issues that may trigger the U18C4 code.

9. Can a low battery cause the U18C4 code to appear?

- A low battery voltage can sometimes cause communication issues between control modules, potentially triggering the U18C4 code. Ensuring the battery is in good condition can help prevent such issues.

10. Will resetting the OBDII system clear the U18C4 code?

- Resetting the OBDII system may temporarily clear the code, but if the underlying issue causing the U18C4 code is not resolved, it is likely to reappear. It is important to diagnose and address the root cause of the problem.

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