AutoCodes – GMC – U1818 2014 GMC Sierra

U1818 2014 GMC Sierra Code - Lost Communication with Engine Control Module on Powertrain Expansion Communication Bus

Quick Answer

Devices connected to the powertrain high-speed General Motor Local Area Network (GMLAN) 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: U1818 2014 GMC Sierra indicates Lost Communication with Engine Control Module on Powertrain Expansion Communication Bus.
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 260

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 Jul 24, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U1818 2014 GMC Sierra Description

Devices connected to the powertrain high-speed General Motor Local Area Network (GMLAN) 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 U1818 2014 GMC Sierra - Lost Communication with Engine Control Module on Powertrain Expansion Communication Bus - AutoCodes.com — U1818 2014 GMC Sierra Code - Lost Communication with Engine Control Module on Powertrain Expansion Communication Bus

What does this mean?

What are the Possible Causes of the DTC U1818 2014 GMC Sierra?

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

How to Fix the DTC U1818 2014 GMC Sierra?

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 U1818 2014 GMC Sierra 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 U1818 2014 GMC Sierra 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 U1818 2014 GMC Sierra Code

1. What are the common symptoms of OBDII code U1818 in a 2014 GMC Sierra?

- Common symptoms include engine stalling, rough idling, poor fuel efficiency, and warning lights on the dashboard.

2. What does the OBDII code U1818 in a 2014 GMC Sierra indicate?

- The code U1818 indicates a loss of communication with the Engine Control Module (ECM) on the Powertrain Expansion Communication Bus.

3. What are some possible causes of the U1818 code in a 2014 GMC Sierra?

- Possible causes include damaged wiring, loose connections, a faulty ECM, a defective communication network module, or software issues.

4. How can I diagnose the U1818 code in a 2014 GMC Sierra?

- Diagnosing the U1818 code involves inspecting the wiring and connections for damage, checking the ECM and communication network module for faults, and using a diagnostic scan tool to monitor communication signals.

5. How can I repair the U1818 code in a 2014 GMC Sierra?

- Repairing the U1818 code may involve repairing or replacing damaged wiring, securing loose connections, replacing a faulty ECM or communication network module, or updating software as needed.

6. Can I drive my 2014 GMC Sierra with the U1818 code present?

- It is not recommended to drive the vehicle with the U1818 code present, as it can lead to further damage and potentially unsafe driving conditions.

7. Will resetting the OBDII code U1818 make it go away permanently?

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

8. How much does it typically cost to repair the U1818 code in a 2014 GMC Sierra?

- The cost of repairing the U1818 code can vary depending on the specific cause of the issue, but it may range from $100 to $500 or more for parts and labor.

9. Can a DIY enthusiast fix the U1818 code issue in a 2014 GMC Sierra?

- DIY enthusiasts with the necessary tools and knowledge of automotive electrical systems may be able to diagnose and repair the U1818 code, but complex issues may require professional assistance.

10. Is the U1818 code a common issue in 2014 GMC Sierra vehicles?

- The U1818 code is not as common as some other OBDII codes, but it can occur in 2014 GMC Sierra vehicles due to various communication network issues.