AutoCodes – Chevrolet – U18C8 Chevrolet

U18C8 Chevrolet 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 Chevrolet 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 565

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 Aug 09, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code U18C8 Chevrolet 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 Chevrolet - Glow Plug Control Module Lost Communication with Engine Control Module - AutoCodes.com — U18C8 Chevrolet Code - Glow Plug Control Module Lost Communication with Engine Control Module

What does this mean?

What are the Possible Causes of the DTC U18C8 Chevrolet?

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 Chevrolet?

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 Chevrolet 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 Chevrolet code?

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

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Information for Specific Chevrolet Models

U18C8 2014 Chevrolet Silverado — Glow Plug Control Module Lost Communication with Engine Control Module
U18C8 2015 Chevrolet Silverado — Glow Plug Control Module Lost Communication with Engine Control Module
U18C8 2016 Chevrolet Silverado — Glow Plug Control Module Lost Communication with Engine Control Module
U18C8 2017 Chevrolet Silverado — Glow Plug Control Module Lost Communication with Engine Control Module
U18C8 2018 Chevrolet Silverado — Glow Plug Control Module Lost Communication with Engine Control Module

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.