AutoCodes – Cadillac – U1147 Cadillac

U1147 Cadillac Code - Lost Communication With Onstar

Quick Answer

Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Common causes include Faulty Onstar, Onstar harness is open or shorted, Onstar 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: U1147 Cadillac indicates Lost Communication With Onstar.
Common causes: Common causes include Faulty Onstar, Onstar harness is open or shorted, Onstar 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 520

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 U1147 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) U1147 is set.

OBDII Code U1147 Cadillac - Lost Communication With Onstar - AutoCodes.com — U1147 Cadillac Code - Lost Communication With Onstar

What does this mean?

What are the Possible Causes of the DTC U1147 Cadillac?

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

How to Fix the DTC U1147 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 U1147 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 U1147 Cadillac Code

1. What are the common symptoms of OBDII code U1147 Cadillac (Lost Communication With Onstar)?

- Common symptoms include Onstar services not functioning properly, loss of communication with the Onstar module, and warning lights on the dashboard.

2. What are the possible causes of OBDII code U1147 Cadillac?

- Possible causes include a faulty Onstar module, damaged wiring or connectors, a blown fuse, software issues, or a communication network problem.

3. How can I diagnose the cause of OBDII code U1147 Cadillac?

- Diagnosis involves checking the Onstar module for proper connection and functionality, inspecting wiring for damage, testing fuses, and using a diagnostic scanner to assess the communication network.

4. What are some tips for repairing OBDII code U1147 Cadillac?

- Repair tips may include replacing the Onstar module if faulty, repairing damaged wiring or connectors, checking and replacing blown fuses, updating software, or addressing communication network issues.

5. Can I repair OBDII code U1147 Cadillac myself, or should I seek professional help?

- Depending on your automotive repair skills and knowledge, you may attempt to repair U1147 Cadillac yourself by following diagnostic procedures and repair tips. However, seeking professional help from a qualified mechanic or dealership is recommended for complex issues.

6. Is it safe to continue driving my Cadillac with OBDII code U1147 (Lost Communication With Onstar)?

- While the vehicle may still be operable with this code, it is advisable to address the issue promptly to ensure the proper functioning of Onstar services and to prevent potential communication failures.

7. Can OBDII code U1147 Cadillac cause any long-term damage to my vehicle?

- If left unresolved, U1147 Cadillac may lead to continued issues with Onstar services and potential communication network problems. Addressing the code promptly can help prevent any long-term damage to your vehicle.

8. How much does it typically cost to repair OBDII code U1147 Cadillac?

- Repair costs for U1147 Cadillac can vary depending on the underlying cause of the issue, the parts needed for repair, and whether you choose to do the repair yourself or seek professional help. Costs may range from a few hundred to over a thousand dollars.

9. Will resetting the OBDII code U1147 Cadillac make it go away permanently?

- Resetting the code may temporarily clear the warning lights, but if the underlying issue is not addressed, the code is likely to reappear. It is essential to diagnose and repair the root cause of U1147 Cadillac for a permanent solution.

10. How can I prevent OBDII code U1147 Cadillac from occurring in the future?

- Regular maintenance, checking the Onstar system for proper functionality, inspecting wiring for damage, and keeping the communication network in good condition can help prevent the recurrence of U1147 Cadillac.