AutoCodes – Chevrolet – U18C8 2018 Chevrolet Silverado

U18C8 2018 Chevrolet Silverado Code - Glow Plug Control Module Lost Communication with Engine Control Module

Quick Answer

Devices connected to the serial data circuits monitor for serial data communications during normal vehicle operation. Common causes include Faulty Engine Control Module (ECM), Engine Control Module harness is open or shorted, Engine 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: U18C8 2018 Chevrolet Silverado indicates Glow Plug Control Module Lost Communication with Engine Control Module.
Common causes: Common causes include Faulty Engine Control Module (ECM), Engine Control Module harness is open or shorted, Engine 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 259

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Jul 24, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U18C8 2018 Chevrolet Silverado 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 be set when a supervised periodic message that includes the transmitter device availability has not been received.

OBDII Code U18C8 2018 Chevrolet Silverado - Glow Plug Control Module Lost Communication with Engine Control Module - AutoCodes.com — U18C8 2018 Chevrolet Silverado Code - Glow Plug Control Module Lost Communication with Engine Control Module

What does this mean?

What are the Possible Causes of the DTC U18C8 2018 Chevrolet Silverado?

Faulty Engine Control Module (ECM)
Engine Control Module harness is open or shorted
Engine Control Module circuit poor electrical connection
Faulty Body Control Module (BCM)

How to Fix the DTC U18C8 2018 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 U18C8 2018 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 U18C8 2018 Chevrolet Silverado code?

Need more information on how to fix the U18C8 2018 Chevrolet Silverado code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U18C8 2018 Chevrolet Silverado code diagnosed by a professional: Find a repair shop in your area

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 U18C8 2018 Chevrolet Silverado Code

1. What are common symptoms of OBDII code U18C8 in a 2018 Chevrolet Silverado?

The common symptoms of code U18C8 include hard starting, rough idling, decreased engine performance, and the glow plug indicator light staying illuminated.

2. What does the OBDII code U18C8 indicate in a 2018 Chevrolet Silverado?

Code U18C8 indicates a communication issue between the Glow Plug Control Module and the Engine Control Module in a 2018 Chevrolet Silverado.

3. What are possible causes of code U18C8 in a 2018 Chevrolet Silverado?

Possible causes of code U18C8 include damaged wiring or connectors, a faulty Glow Plug Control Module, a malfunctioning Engine Control Module, or a software issue.

4. How can I diagnose the OBDII code U18C8 in my 2018 Chevrolet Silverado?

Diagnosing code U18C8 involves checking the wiring and connectors for damage, testing the Glow Plug Control Module and Engine Control Module, and scanning for any other related fault codes.

5. Can I continue driving my 2018 Chevrolet Silverado with code U18C8?

It is not recommended to drive your vehicle with code U18C8 as it can lead to starting issues and potential engine performance problems. It is advisable to address the issue promptly.

6. How can I repair OBDII code U18C8 in my 2018 Chevrolet Silverado?

Repairing code U18C8 may involve repairing or replacing damaged wiring or connectors, replacing the Glow Plug Control Module or Engine Control Module if faulty, and performing any necessary software updates.

7. Is it possible to reset OBDII code U18C8 in a 2018 Chevrolet Silverado without fixing the underlying issue?

Resetting the code without fixing the underlying issue is not recommended, as the problem will persist and may lead to more severe issues over time. It's best to address the root cause of the code.

8. Can extreme weather conditions cause code U18C8 to trigger in a 2018 Chevrolet Silverado?

Yes, extreme weather conditions can sometimes affect the communication between modules, leading to code U18C8. Ensuring proper insulation and protection of electrical components can help prevent this issue.

9. How long does it typically take to repair OBDII code U18C8 in a 2018 Chevrolet Silverado?

The repair time for code U18C8 can vary depending on the exact cause of the issue. Simple fixes like repairing a wiring issue may take a short time, while replacing modules or conducting extensive diagnostics can take longer.

10. Is professional assistance recommended for resolving OBDII code U18C8 in a 2018 Chevrolet Silverado?

Due to the complexity of diagnosing and repairing communication issues between modules, seeking professional assistance from a certified mechanic or dealership is recommended for efficiently resolving code U18C8 in a 2018 Chevrolet Silverado.