AutoCodes – GMC – U0074 2018 GMC Sierra

U0074 2018 GMC Sierra Code - Control Module Communication Powertrain Expansion CAN Bus Off Malfunction

Quick Answer

The devices connected to the chassis high-speed General Motor Local Area Network (GMLAN) serial data circuits monitor for serial data communications during normal vehicle operation. Common causes include Diagnosis of this Diagnostic Trouble Code (DTC) is accomplished via the vehicle symptom(s), Check for more codes, Faulty Control Module. 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: U0074 2018 GMC Sierra indicates Control Module Communication Powertrain Expansion CAN Bus Off Malfunction.
Common causes: Common causes include Diagnosis of this Diagnostic Trouble Code (DTC) is accomplished via the vehicle symptom(s), Check for more codes, Faulty Control Module.
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 319

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 U0074 2018 GMC Sierra Description

The devices connected to the chassis 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 when the ignition switch is in any position other than OFF. The chassis high-speed GMLAN serial data bus uses terminating resistors that are in parallel with the chassis high-speed GMLAN (+) and (-) circuits. The Diagnostic Trouble Code (DTC) will be set when a supervised periodic message that includes the transmitter device availability has not been received for more than 450 ms.

OBDII Code U0074 2018 GMC Sierra - Control Module Communication Powertrain Expansion CAN Bus Off Malfunction - AutoCodes.com — U0074 2018 GMC Sierra Code - Control Module Communication Powertrain Expansion CAN Bus Off Malfunction

What does this mean?

What are the Possible Causes of the DTC U0074 2018 GMC Sierra?

Diagnosis of this Diagnostic Trouble Code (DTC) is accomplished via the vehicle symptom(s)
Check for more codes
Faulty Control Module
Control Module harness is open or shorted
Control Module circuit poor electrical connection

How to Fix the DTC U0074 2018 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 U0074 2018 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 U0074 2018 GMC Sierra code?

Need more information on how to fix the U0074 2018 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 U0074 2018 GMC Sierra Code

1. What does the OBDII code U0074 mean on a 2018 GMC Sierra?

The U0074 code indicates a "Control Module Communication Powertrain Expansion CAN Bus Off Malfunction," meaning there is an issue with the vehicle's communication network.

2. What are common symptoms of code U0074 on the 2018 GMC Sierra?

Symptoms may include the check engine light turning on, erratic transmission behavior, loss of communication with certain control modules, or the vehicle failing to start.

3. What causes the U0074 code on a 2018 GMC Sierra?

Common causes include damaged or shorted wiring in the CAN bus system, a faulty control module, loose connections, or a malfunctioning CAN bus communication line.

4. Can a weak battery cause the U0074 code on a 2018 GMC Sierra?

Yes, a weak or failing battery can cause voltage issues, potentially leading to communication errors like the U0074 code.

5. How do you diagnose the U0074 code on a 2018 GMC Sierra?

Diagnosis involves using a scan tool to check for additional codes, inspecting wiring and connectors in the CAN bus system, and testing control module power and ground connections.

6. Is the U0074 code serious on a 2018 GMC Sierra?

Yes, it can be serious as it impacts communication between critical modules, possibly leading to drivability issues or a complete loss of vehicle function.

7. How do you fix code U0074 on a 2018 GMC Sierra?

Repairs may include fixing or replacing damaged wiring, reconnecting loose connectors, replacing a faulty control module, or resetting the system after repairs.

8. Can driving with the U0074 code cause further damage to my GMC Sierra?

Yes, ignoring the code could lead to further electrical or module damage, as well as potential safety issues if the problem disrupts critical systems.

9. What tools are needed to troubleshoot the U0074 code on a 2018 GMC Sierra?

A diagnostic scan tool, a multimeter for testing electrical continuity, and a wiring diagram of the CAN bus system are essential for troubleshooting.

10. How much does it cost to fix the U0074 code on a 2018 GMC Sierra?

The cost varies depending on the issue, but it can range from $100 for minor wiring repairs to over $1,000 if a control module needs replacement and reprogramming.