AutoCodes – Generic – U18C4

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

Quick Answer

Devices connected to the serial data circuits monitor for serial data communications during normal vehicle operation. Common causes include Faulty Video Processing Control Module, Video Processing Control Module harness is open or shorted, Video Processing Control Module circuit poor electrical connection. 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, Video Processing Control Module harness is open or shorted, Video Processing Control Module circuit poor electrical connection.
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.

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Code Popularity 700

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jun 09, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U18C4 Description

Devices connected to the serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the devices. The devices have prerecorded information about what messages are needed to be exchanged on the serial data circuits, for each virtual network. The messages are supervised and also, some periodic messages are used by the receiver device as an availability indication of the transmitter device. Each message contains the identification number of the transmitter device. The Diagnostic Trouble Code (DTC) will set a supervised periodic message that includes the transmitter device availability that has not been received.

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

What does this mean?

What are the Possible Causes of the DTC U18C4?

Faulty Video Processing Control Module
Video Processing Control Module harness is open or shorted
Video Processing Control Module circuit poor electrical connection

How to Fix the DTC U18C4?

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 U18C4 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 U18C4 code?

Need more information on how to fix the U18C4 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U18C4 code diagnosed by a professional: Find a repair shop in your area

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.