AutoCodes – Buick – U0073 Buick

U0073 Buick Code - Control Module Communication Bus OFF

Quick Answer

Modules connected to the high-speed General Motor Local Area Network (GMLAN) serial data circuits monitor for serial data communications during normal vehicle operation. Common causes include Faulty Module/Device that is not communicating, Module/Device harness is open or shorted, Module/Device 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: U0073 Buick indicates Control Module Communication Bus OFF.
Common causes: Common causes include Faulty Module/Device that is not communicating, Module/Device harness is open or shorted, Module/Device 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 18,784

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 19, 2023

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U0073 Buick Description

Modules connected to the 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 modules. The modules have prerecorded information about what messages need 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 module as an availability indication of the transmitter module. The supervision time-out period is 250 ms. Each message contains the identification number of the transmitter module. The Diagnostic Trouble Code (DTC) will be set when the device setting the DTC has attempted to establish communications on the serial data circuits more than 3 times in 5 s.

OBDII Code U0073 Buick - Control Module Communication Bus OFF - AutoCodes.com — U0073 Buick Code - Control Module Communication Bus OFF

What does this mean?

What are the Possible Causes of the DTC U0073 Buick?

Faulty Module/Device that is not communicating
Module/Device harness is open or shorted
Module/Device circuit poor electrical connection

How to Fix the DTC U0073 Buick?

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 U0073 Buick 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.

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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 U0073 Buick Code

1. What does OBDII code U0073 mean on a Buick?

U0073 indicates a communication problem in the Control Area Network (CAN) bus, where one or more control modules are unable to communicate properly.

2. What are the common symptoms of code U0073 on a Buick?

Symptoms may include a check engine light, erratic vehicle performance, failure of certain systems like ABS or traction control, and difficulty starting the vehicle.

3. What causes the U0073 code to appear on a Buick?

The code can be caused by a faulty control module, damaged wiring or connectors in the CAN bus network, a weak battery, or issues with the CAN bus itself.

4. Can a weak battery trigger the U0073 code on a Buick?

Yes, a weak or failing battery can cause voltage issues that disrupt communication between control modules, triggering the U0073 code.

5. How can I fix the U0073 code on my Buick?

Start by checking the battery and charging system, inspecting CAN bus wiring and connectors for damage, and scanning for additional codes to pinpoint the faulty module.

6. Is it safe to drive my Buick with the U0073 code?

Driving with this code can lead to unpredictable behavior in critical systems like braking and steering. Itâ€™s best to address the issue promptly.

7. How do I diagnose the U0073 code on a Buick?

Use a diagnostic scanner capable of reading CAN bus data to check for module communication issues. Inspect wiring, connectors, and voltage levels for faults.

8. Can a damaged CAN bus wire cause the U0073 code on a Buick?

Yes, damaged or shorted CAN bus wires can disrupt communication between control modules and trigger the U0073 code.

9. Do I need to replace a control module to fix the U0073 code on a Buick?

Not always. The issue could be related to wiring, connectors, or a power/ground fault. Replace a module only if diagnostics confirm it's faulty.

10. How much does it cost to fix the U0073 code on a Buick?

Repair costs vary depending on the cause. Simple fixes like repairing wiring may cost $100-$200, while replacing a control module could cost $500 or more.