AutoCodes – Buick – U1128 Buick

U1128 Buick Code - Lost Communications With Radio

Quick Answer

Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Common causes include Faulty Radio, Radio harness is open or shorted, Radio 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: U1128 Buick indicates Lost Communications With Radio.
Common causes: Common causes include Faulty Radio, Radio harness is open or shorted, Radio 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 644

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 22, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U1128 Buick Description

Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. When a module receives a message for a critical operating parameter, the module records the identification number of the module which sent the message for the state of health monitoring/node alive messages. A critical operating parameter is one which, when not received, requires that the module use a default value for that parameter. Once an identification number is learned by a module, it will monitor for that module node alive message. Each module on the class 2 serial data circuit is required to send a Node Alive message every 2 seconds. When no message is detected from a learned identification number for 5 seconds, a Diagnostic Trouble Code (DTC) U1128 is set.

OBDII Code U1128 Buick - Lost Communications With Radio - AutoCodes.com — U1128 Buick Code - Lost Communications With Radio

What does this mean?

What are the Possible Causes of the DTC U1128 Buick?

Faulty Radio
Radio harness is open or shorted
Radio circuit poor electrical connection

How to Fix the DTC U1128 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 U1128 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 U1128 Buick Code

1. What are common symptoms of the OBDII code U1128 "Lost Communications With Radio" in a Buick?

- Common symptoms include the radio not functioning properly, loss of audio, and potential issues with other vehicle systems controlled by the radio.

2. What are the possible causes of the U1128 code in a Buick?

- Possible causes may include a faulty radio unit, damaged wiring or connectors, a blown fuse, or a communication error with the vehicle's network.

3. How can I diagnose the U1128 code related to lost communications with the radio in my Buick?

- Diagnose the code by checking the radio unit for power and ground, inspecting the wiring for any damage, and using a diagnostic scanner to identify communication faults with the radio module.

4. Can a U1128 code be triggered by a disconnected or aftermarket radio installation in a Buick?

- Yes, a U1128 code can be triggered by a disconnected factory radio or an incompatible aftermarket radio that disrupts communication on the vehicle's network.

5. What are some repair tips for resolving the U1128 code in a Buick?

- Repair tips include checking and repairing any damaged wiring, ensuring the radio unit is properly connected, resetting the radio module, and clearing the code with a diagnostic scanner.

6. Is it safe to continue driving with the U1128 code related to lost communications with the radio in a Buick?

- While the vehicle may still be driveable, it is recommended to address the issue promptly to avoid potential problems with other vehicle systems that rely on communication with the radio.

7. Can a U1128 code be a false alarm in a Buick, and how can this be verified?

- Yes, a U1128 code can sometimes be a false alarm caused by a temporary communication glitch. It can be verified by clearing the code and monitoring if it returns after some time.

8. Will resetting the U1128 code resolve the issue permanently in a Buick?

- Resetting the code may temporarily clear the warning, but if the underlying issue such as a faulty radio or wiring problem persists, the code is likely to return.

9. Are there any recalls or technical service bulletins related to the U1128 code in Buick vehicles?

- It is recommended to check with the manufacturer or authorized service centers for any recalls or technical service bulletins related to the U1128 code in specific Buick models.

10. Should I attempt to repair the U1128 code related to lost communications with the radio in my Buick myself, or seek professional help?

- While some basic checks and repairs can be done by DIY enthusiasts, complex diagnosis and repairs related to the U1128 code may require professional assistance from a qualified mechanic or dealership.