AutoCodes – Chevrolet – U0074 Chevrolet

U0074 Chevrolet 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 Chevrolet 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 16,912

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 Chevrolet 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 Chevrolet - Control Module Communication Powertrain Expansion CAN Bus Off Malfunction - AutoCodes.com — U0074 Chevrolet Code - Control Module Communication Powertrain Expansion CAN Bus Off Malfunction

What does this mean?

What are the Possible Causes of the DTC U0074 Chevrolet?

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 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 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 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 U0074 Chevrolet code?

Need more information on how to fix the U0074 Chevrolet code? Get Access to Factory Service Manuals

Need Help with the Code?

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Information for Specific Chevrolet Models

U0074 2014 Chevrolet Silverado — Control Module Communication Powertrain Expansion CAN Bus Off Malfunction
U0074 2015 Chevrolet Silverado — Control Module Communication Powertrain Expansion CAN Bus Off Malfunction
U0074 2016 Chevrolet Silverado — Control Module Communication Powertrain Expansion CAN Bus Off Malfunction
U0074 2017 Chevrolet Silverado — Control Module Communication Powertrain Expansion CAN Bus Off Malfunction
U0074 2018 Chevrolet Silverado — Control Module Communication Powertrain Expansion CAN Bus Off Malfunction

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 Chevrolet Code

1. What are common symptoms of the U0074 code in a Chevrolet vehicle?

- Common symptoms include the check engine light coming on, poor vehicle performance, stalling, and difficulty starting the engine.

2. What can cause the U0074 code to appear in a Chevrolet?

- The U0074 code is typically caused by issues with the Control Area Network (CAN) communication system, such as damaged wiring, loose connections, or a faulty control module.

3. How can I diagnose the U0074 code in my Chevrolet?

- To diagnose the U0074 code, a mechanic will use an OBDII scanner to retrieve the specific fault code and then perform a thorough inspection of the communication system components to pinpoint the issue.

4. Can I still drive my Chevrolet with the U0074 code present?

- It is not recommended to drive your Chevrolet with the U0074 code present, as it can lead to further damage and potential safety hazards. Have the issue diagnosed and repaired promptly.

5. How can I repair the U0074 code in my Chevrolet?

- Repairing the U0074 code in a Chevrolet typically involves fixing any wiring issues, repairing or replacing damaged components, and resetting the fault code using an OBDII scanner.

6. Are there any DIY tips for fixing the U0074 code in a Chevrolet?

- DIY tips for fixing the U0074 code include checking for loose connections, inspecting wiring for damage, and ensuring all control modules are properly connected and functioning.

7. What other codes might be related to the U0074 code in a Chevrolet?

- Other related codes might include U0073 (Control Module Communication Bus A Off) and U0100 (Lost Communication with ECM/PCM "A").

8. How long does it take to repair the U0074 code in a Chevrolet?

- The time to repair the U0074 code in a Chevrolet can vary depending on the exact cause of the issue and the availability of parts. It could take anywhere from a few hours to a full day.

9. Will resetting the U0074 code make it go away permanently?

- Resetting the U0074 code may temporarily clear the check engine light, but if the underlying issue is not resolved, the code is likely to reappear. It's important to diagnose and fix the root cause.

10. Can a faulty battery or alternator cause the U0074 code in a Chevrolet?

- Yes, a faulty battery or alternator can potentially cause the U0074 code in a Chevrolet due to disruptions in power supply affecting the communication system. It's recommended to check these components if the code persists.