U1049 – OBD-II DTC

OBD-II DTC U1049 – SCP (J1850) Invalid or Missing Data for Primary Id

DTC U1049 meaning

DTC U1049 refers to a communication error within the vehicle’s network, specifically indicating “Invalid or Missing Data for Primary Id.” This code is associated with the SCP (Standard Corporate Protocol) communication system, which is part of the J1850 protocol. It suggests that the vehicle’s control modules are unable to communicate properly, leading to a lack of essential data transmission.

DTC U1049 symptoms

Common symptoms associated with DTC U1049 may include:

• Warning lights illuminated on the dashboard, such as the check engine light.
• Loss of functionality in certain electronic features or systems.
• Erratic behavior of the vehicle’s electronic components.
• Difficulty in diagnosing other DTCs due to communication issues.

DTC U1049 causes

Several factors can lead to the occurrence of DTC U1049, including:

• Faulty wiring or connectors in the SCP network.
• Defective control modules that are unable to send or receive data.
• Corrosion or damage to the connectors or terminals.
• Software issues or bugs within the control modules.
• Interference from aftermarket devices or modifications.

DTC U1049 seriousness

DTC U1049 can be considered serious as it indicates a failure in communication between control modules. This can lead to:

• Inability to monitor or control critical vehicle systems.
• Potential safety risks if essential systems are compromised.
• Increased difficulty in diagnosing other issues due to communication failures.

How to diagnose DTC U1049

To diagnose DTC U1049, follow these steps:

1. Use an OBD-II scanner to confirm the presence of DTC U1049.
2. Check for any additional DTCs that may provide more context.
3. Inspect the wiring and connectors related to the SCP network for damage or corrosion.
4. Test the affected control modules for proper operation.
5. Verify the integrity of the vehicle’s battery and charging system.
6. Check for software updates or reprogramming needs for the control modules.

How to fix DTC U1049 step-by-step instructions

To fix DTC U1049, follow these steps:

1. Inspect and repair any damaged wiring or connectors in the SCP network.
2. Replace any faulty control modules identified during diagnosis.
3. Clean any corroded connectors and ensure a secure connection.
4. Update or reprogram control modules if necessary.
5. Clear the DTC using an OBD-II scanner and test drive the vehicle.
6. Monitor for the reoccurrence of the DTC or any related symptoms.

How to erase DTC U1049

To erase DTC U1049, follow these steps:

1. Connect an OBD-II scanner to the vehicle’s diagnostic port.
2. Turn on the vehicle’s ignition without starting the engine.
3. Access the DTC menu on the scanner and locate DTC U1049.
4. Select the option to clear or erase the DTC.
5. Turn off the ignition and disconnect the scanner.
6. Start the vehicle and monitor for any reappearance of the DTC.

Recommended tools for OBD-II diagnostics

Explore our expert picks: The Best OBD2 Scanners for 2025

Easy-to-use Multimeter for reliable diagnostics: AstroAI Auto-ranging Multimeter

Some of the links on this page may be affiliate links, which means we may earn a small commission if you make a purchase. This helps us keep our DTC database up to date and provide valuable content for free. We only recommend products that we have tested and believe to be the best in their class.