AutoCodes – Cadillac – U1129 Cadillac

U1129 Cadillac Code - Lost Communications With Audio Amplifier

Quick Answer

Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Common causes include Faulty Audio Amplifier, Audio Amplifier harness is open or shorted, Audio Amplifier 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: U1129 Cadillac indicates Lost Communications With Audio Amplifier.
Common causes: Common causes include Faulty Audio Amplifier, Audio Amplifier harness is open or shorted, Audio Amplifier 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 1,149

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 U1129 Cadillac 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) U1129 is set.

OBDII Code U1129 Cadillac - Lost Communications With Audio Amplifier - AutoCodes.com — U1129 Cadillac Code - Lost Communications With Audio Amplifier

What does this mean?

What are the Possible Causes of the DTC U1129 Cadillac?

Faulty Audio Amplifier
Audio Amplifier harness is open or shorted
Audio Amplifier circuit poor electrical connection

How to Fix the DTC U1129 Cadillac?

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 U1129 Cadillac 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 U1129 Cadillac Code

1. What are common symptoms of OBDII code U1129 in a Cadillac related to lost communications with the audio amplifier?

- Common symptoms include no sound from the audio system, malfunctioning speakers, and issues with volume control.

2. What are some possible causes of OBDII code U1129 in a Cadillac indicating lost communications with the audio amplifier?

- Possible causes include a faulty audio amplifier, wiring or connection issues, blown fuses, or a software glitch.

3. How can I diagnose the reason behind OBDII code U1129 in my Cadillac for lost communications with the audio amplifier?

- You can use a diagnostic scanner to retrieve the code, check the audio system's connections and wiring, inspect the audio amplifier for any visible damage, and test fuses related to the audio system.

4. Is it safe to continue driving my Cadillac with the U1129 OBDII code indicating lost communications with the audio amplifier?

- While it is generally safe to drive with this code, it is recommended to address the issue promptly to avoid further audio system malfunctions.

5. Can resetting the OBDII code U1129 in my Cadillac fix the lost communications with the audio amplifier issue?

- Resetting the code may temporarily resolve the issue, but it's essential to investigate and address the root cause to prevent the problem from reoccurring.

6. Are there specific repair tips for fixing OBDII code U1129 in a Cadillac related to lost communications with the audio amplifier?

- Repair tips include checking and repairing any damaged wiring, ensuring proper connections to the audio amplifier, and replacing the audio amplifier if necessary.

7. How much can I expect to pay to repair OBDII code U1129 in my Cadillac indicating lost communications with the audio amplifier?

- Repair costs can vary depending on the specific issue, but they may range from a few hundred to a thousand dollars, including parts and labor.

8. Can extreme weather conditions or water damage cause OBDII code U1129 in a Cadillac for lost communications with the audio amplifier?

- Yes, extreme weather conditions or water damage can lead to electrical issues, including communication problems with the audio amplifier, triggering the U1129 code.

9. Are there any recalls or technical service bulletins related to OBDII code U1129 in Cadillacs for lost communications with the audio amplifier?

- It's recommended to check with a Cadillac dealership or online databases for any relevant recalls or technical service bulletins addressing this specific issue.

10. Does fixing OBDII code U1129 in a Cadillac require specialized tools or expertise?

- While basic knowledge of automotive electrical systems is helpful, specialized tools such as diagnostic scanners and wiring diagrams may be needed to diagnose and repair the lost communications with the audio amplifier issue.