AutoCodes – Generic – U1049

U1049 Code - Invalid Or Missing Data For Primary Id

Quick Answer

Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Common causes include Faulty Module that is not communicating, Module harness is open or shorted, Module 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: U1049 indicates Invalid Or Missing Data For Primary Id.
Common causes: Common causes include Faulty Module that is not communicating, Module harness is open or shorted, Module 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 6,975

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 U1049 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 State of Health monitoring. A critical operating parameter is one which, when not received, requires that the module use a default value for that parameter. When a module does not associate an identification number with at least one critical parameter within 5 seconds of beginning serial data communication, the Diagnostic Trouble Code (DTC) is set.

OBDII Code U1049 - Invalid Or Missing Data For Primary Id - AutoCodes.com — U1049 Code - Invalid Or Missing Data For Primary Id

What does this mean?

What are the Possible Causes of the DTC U1049?

Faulty Module that is not communicating
Module harness is open or shorted
Module circuit poor electrical connection

How to Fix the DTC U1049?

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 U1049 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.

Need more information about the U1049 code?

Need more information on how to fix the U1049 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U1049 code diagnosed by a professional: Find a repair shop in your area

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 U1049 Code

1. What does OBDII code U1049 mean?

U1049 indicates "Invalid Or Missing Data For Primary ID," which typically refers to a communication issue between modules in the vehicle's network.

2. What are the common symptoms of code U1049?

Symptoms may include warning lights on the dashboard, erratic vehicle behavior, loss of communication with certain modules, or failure of specific systems like ABS or traction control.

3. What causes the U1049 code to appear?

Common causes include faulty wiring or connectors, damaged or malfunctioning control modules, software glitches, or network communication errors.

4. How can I diagnose code U1049?

Start by inspecting the wiring and connectors, check for damaged modules, and use a diagnostic scanner to identify which module is failing to communicate properly.

5. Can a weak battery cause code U1049?

Yes, a weak or failing battery can cause voltage drops that disrupt communication between vehicle modules, potentially triggering U1049.

6. Is it safe to drive with code U1049?

It depends on the severity of the issue. If critical systems like ABS or traction control are affected, driving may be unsafe, and the vehicle should be inspected promptly.

7. How do I fix code U1049?

Repairs may involve checking and replacing damaged wiring or connectors, reprogramming or replacing faulty modules, or updating module software.

8. Can a faulty ECU cause code U1049?

Yes, a malfunctioning ECU (Engine Control Unit) or other control modules can fail to communicate, leading to the U1049 code.

9. Will clearing the code fix U1049 permanently?

Clearing the code may temporarily remove it, but if the underlying issue isn't resolved, it will likely reappear.

10. Do I need professional help for code U1049?

If youâ€™re unable to diagnose or repair the issue yourself, seeking professional assistance is recommended, especially for complex module communication errors.