AutoCodes – GMC – U18A2 2014 GMC Sierra

U18A2 2014 GMC Sierra Code - Lost Communication with Fuel Pump Driver Control Module

Quick Answer

Devices connected to the serial data circuits monitor for serial data communications during normal vehicle operation. Common causes include Faulty Fuel Pump Driver Control Module, Fuel Pump Driver Control Module harness is open or shorted, Fuel Pump Driver 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: U18A2 2014 GMC Sierra indicates Lost Communication with Fuel Pump Driver Control Module.
Common causes: Common causes include Faulty Fuel Pump Driver Control Module, Fuel Pump Driver Control Module harness is open or shorted, Fuel Pump Driver 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 336

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 Apr 14, 2023

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code U18A2 2014 GMC Sierra 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 U18A2 2014 GMC Sierra - Lost Communication with Fuel Pump Driver Control Module - AutoCodes.com — U18A2 2014 GMC Sierra Code - Lost Communication with Fuel Pump Driver Control Module

What does this mean?

What are the Possible Causes of the DTC U18A2 2014 GMC Sierra?

Faulty Fuel Pump Driver Control Module
Fuel Pump Driver Control Module harness is open or shorted
Fuel Pump Driver Control Module circuit poor electrical connection

How to Fix the DTC U18A2 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 does this mean?

Code Tech Notes

There is a Factory Service Bulletin for the following Chevrolet Models:

- 2014-2018 Chevrolet Silverado
- 2015-2018 Chevrolet Suburban
- 2015-2018 Chevrolet Tahoe

If the Diagnostic Trouble Codes (DTC) P2635, U0074, and/or U18A2 are set, it may be found that the actual fuel pressure (low-pressure system) will be reading substantially higher than desired fuel pressure, in this case, the cause of the problem is a loss of communication between Engine Control Module (ECM) and Fuel Pump Control Module (FPCM).

- Diagnose for any communication DTCs set (U0074 would take priority over U18A2 if both set) before addressing DTC P2635.
- If DTC P2635 is not resolved by correcting the communication DTCs, only then should diagnose the DTC P2635.
- It has been found that a communication issue between the FPCM and ECM can potentially induce DTC P2635 and result in a pressure differential between actual and desired fuel system pressures.
- If the actual fuel pressure is substantially higher than desired (10 psi / 70 kPa or more), replacement of the fuel pump control module or fuel system components typically will not resolve this issue.
- If the actual fuel pressure is substantially lower than desired (10 psi / 70 kPa or more), this Factory Service Bulletin would NOT apply. It would be recommended to diagnose low actual fuel pressure.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the U18A2 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 U18A2 2014 GMC Sierra code?

Need more information on how to fix the U18A2 2014 GMC Sierra code? Get Access to Factory Service Manuals

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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 U18A2 2014 GMC Sierra Code

1. What are the common symptoms of OBDII code U18A2 in a 2014 GMC Sierra?

- Common symptoms include issues with the fuel pump operation, engine stalling, difficulty starting the vehicle, and the Check Engine Light illuminating.

2. What does the OBDII code U18A2 "Lost Communication with Fuel Pump Driver Control Module" mean for a 2014 GMC Sierra?

- This code indicates a communication problem between the vehicle's onboard computer and the fuel pump driver control module, potentially leading to fuel delivery issues.

3. What are the possible causes of the U18A2 code in a 2014 GMC Sierra?

- Potential causes include a faulty fuel pump driver control module, damaged wiring or connectors, a blown fuse, software issues, or a malfunctioning PCM.

4. How can I diagnose the issue causing code U18A2 in my 2014 GMC Sierra?

- Diagnosing the problem may involve checking the fuel pump driver control module for proper functioning, inspecting the wiring and connectors for damage, and using a scan tool to communicate with the vehicle's systems.

5. Is it safe to drive my 2014 GMC Sierra with the U18A2 code present?

- It is not recommended to drive the vehicle with this code active, as it can lead to potential fuel pump malfunctions and engine performance issues.

6. How can I repair the "Lost Communication with Fuel Pump Driver Control Module" issue in my 2014 GMC Sierra?

- Repair options may include replacing the fuel pump driver control module, repairing damaged wiring or connectors, resetting the system, or updating the vehicle's software.

7. Can I reset the U18A2 code in my 2014 GMC Sierra without fixing the underlying issue?

- While you can clear the code using a scan tool, it is crucial to address the root cause of the problem to prevent it from recurring and potentially causing further damage.

8. Are there any DIY tips for troubleshooting the U18A2 code in a 2014 GMC Sierra?

- DIY tips may include checking for loose or damaged connections, inspecting the fuse related to the fuel pump control module, and ensuring the fuel pump is receiving power.

9. How much does it typically cost to repair the U18A2 code in a 2014 GMC Sierra?

- Repair costs can vary depending on the exact cause of the issue, but they may range from a few hundred dollars for simple fixes like wiring repairs to over a thousand dollars for module replacements.

10. Can a faulty fuel pump driver control module cause other issues besides the U18A2 code in a 2014 GMC Sierra?

- Yes, a faulty fuel pump driver control module can lead to various fuel delivery problems, engine performance issues, and potential drivability concerns beyond just triggering the U18A2 diagnostic trouble code.