AutoCodes – GMC – U18C4 GMC

U18C4 GMC 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 GMC 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 464

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

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 GMC?

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 GMC 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 GMC code?

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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 GMC Code

1. What are the common symptoms of OBDII code U18C4 GMC?

- Common symptoms include loss of video display on the infotainment system, malfunctioning rearview camera, and issues with other video-related systems.

2. What are the possible causes of the U18C4 GMC code?

- The code U18C4 typically indicates a communication error between the vehicle's control modules and the Video Processing Control Module on the Low Speed CAN Bus. This can be caused by wiring issues, faulty modules, or software glitches.

3. How can I diagnose the U18C4 GMC code?

- Diagnosing the U18C4 code involves using a professional OBDII scanner to read the code and perform a thorough inspection of the wiring connections related to the Video Processing Control Module.

4. Can I drive my vehicle with the U18C4 code present?

- It is generally not recommended to drive the vehicle with the U18C4 code present, as it may result in the loss of important video-related functions that could affect safety and convenience.

5. How can I repair the U18C4 GMC code?

- Repairing the U18C4 code involves addressing the underlying communication issue by checking and repairing any damaged wiring, replacing faulty control modules, and updating software as necessary.

6. Is the U18C4 code a common problem in GMC vehicles?

- The U18C4 code is not as common as other OBDII codes, but it can occur in GMC vehicles equipped with video processing control modules.

7. Can a DIY enthusiast fix the U18C4 code at home?

- While some basic troubleshooting steps can be taken at home, diagnosing and repairing the U18C4 code may require specialized tools and expertise, making it more suitable for professional technicians.

8. Are there any recalls related to the U18C4 GMC code?

- It's recommended to check with the manufacturer or a GMC dealership to inquire about any recalls or service bulletins related to the U18C4 code for your specific vehicle model and year.

9. Will resetting the OBDII code clear the U18C4 GMC code permanently?

- Resetting the OBDII code may temporarily clear the code, but if the underlying issue causing the U18C4 code is not addressed, it is likely to reappear.

10. How much does it typically cost to repair the U18C4 GMC code?

- The cost of repairing the U18C4 code can vary depending on the specific cause of the issue, but it may involve expenses for parts, labor, and diagnostic fees, which can range from a few hundred to over a thousand dollars.