AutoCodes – Pontiac – U1128 Pontiac

U1128 Pontiac 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 Pontiac 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 665

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 24, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U1128 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) U1128 is set.

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

What does this mean?

What are the Possible Causes of the DTC U1128 Pontiac?

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

How to Fix the DTC U1128 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 U1128 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 U1128 Pontiac Code

1. What does the OBDII code U1128 mean on a Pontiac?

Code U1128 indicates that there is a communication failure between the vehicle's radio and other modules in the network.

2. What are the common symptoms of code U1128 in a Pontiac?

Common symptoms include the radio not functioning, loss of audio output, intermittent sound issues, or other infotainment system malfunctions.

3. What causes the U1128 code to appear on a Pontiac?

The code is typically caused by a faulty radio module, wiring or connector issues, a network communication problem, or a software glitch.

4. Can code U1128 affect other systems in my Pontiac?

Yes, communication issues with the radio can sometimes interfere with other modules like Bluetooth or navigation, but it usually does not impact critical driving functions.

5. How do I diagnose the U1128 code on my Pontiac?

Start by inspecting the radio module, checking for loose or damaged wiring and connectors, and using a scan tool to verify communication on the CAN bus network.

6. Is a faulty radio the only reason for the U1128 code?

No, other possible reasons include a bad CAN bus connection, failing control module, or outdated software in the radio or related systems.

7. Can I fix the U1128 code myself on my Pontiac?

If the issue is due to a loose connector or visible wiring damage, you may be able to fix it yourself. However, advanced diagnostics may require professional tools and expertise.

8. Will resetting the ECU clear the U1128 code on my Pontiac?

Resetting the ECU may temporarily clear the code, but the underlying issue must be resolved to prevent the code from returning.

9. What tools are needed to troubleshoot the U1128 code?

Youâ€™ll need an OBDII scan tool capable of reading manufacturer-specific codes and a multimeter to check for wiring issues.

10. How much does it cost to repair the U1128 code on a Pontiac?

Repair costs depend on the issue. Fixing wiring problems might cost $50-$200, while replacing the radio module could range from $300-$800, including parts and labor.