AutoCodes – Pontiac – U1129 Pontiac

U1129 Pontiac 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 Pontiac 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 545

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Apr 24, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U1129 Pontiac 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 Pontiac - Lost Communications With Audio Amplifier - AutoCodes.com — U1129 Pontiac Code - Lost Communications With Audio Amplifier

What does this mean?

What are the Possible Causes of the DTC U1129 Pontiac?

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

How to Fix the DTC U1129 Pontiac?

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 Pontiac 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 Pontiac Code

What does the OBDII code U1129 mean for my Pontiac?

U1129 indicates a "Lost Communications With Audio Amplifier" error, meaning the vehicle's computer cannot communicate with the audio amplifier.

What are the common symptoms of the U1129 code?

Symptoms may include a malfunctioning audio system, such as no sound, static, or intermittent audio issues, as well as potential warning lights on the dashboard.

What could cause the U1129 code to trigger?

Possible causes include a faulty audio amplifier, damaged wiring or connectors, blown fuses, or issues with the vehicle's central control module.

How can I diagnose the U1129 code?

Start by checking for any blown fuses related to the audio system, then inspect wiring and connectors for damage. Use a scan tool to check for any other related codes.

Are there specific repairs for the U1129 code?

Repairs may involve replacing the audio amplifier, repairing or replacing damaged wiring, or resetting the vehicle's modules if they have lost communication.

Can I drive my Pontiac with the U1129 code?

While it's generally safe to drive, you may experience issues with the audio system. It's advisable to address the code to restore full functionality.

How do I clear the U1129 code from my vehicle's system?

You can clear the code using an OBDII scanner after addressing the underlying issue. Disconnecting the battery for a few minutes may also reset the system but is not guaranteed to clear the code.

Is it necessary to take my Pontiac to a professional for the U1129 code?

If you're not comfortable diagnosing or repairing electrical issues, it's best to consult a professional mechanic to ensure proper handling of the problem.

What is the cost range for repairing the U1129 code?

Repair costs can vary widely, typically ranging from $50 to $300, depending on whether it's a simple wiring fix or a replacement of the audio amplifier.