U1189 – OBD-II DTC

OBD-II DTC U1189 – SCP (J1850) Invalid or Missing Data for Primary Id

DTC U1189 meaning

DTC U1189 refers to a diagnostic trouble code indicating “Invalid or Missing Data for Primary Id” in vehicles using the SCP (J1850) communication protocol. This code suggests that the vehicle’s onboard diagnostic system has detected an issue with the data being transmitted from one of the modules, which may be affecting the overall performance and functionality of the vehicle’s systems.

DTC U1189 symptoms

Common symptoms associated with DTC U1189 may include:

• Illumination of the check engine light
• Erratic or non-functional vehicle systems
• Communication issues between modules
• Loss of certain vehicle features or functions

DTC U1189 causes

Several factors can lead to the occurrence of DTC U1189, including:

• Faulty or damaged wiring in the SCP network
• Defective or malfunctioning control modules
• Corrosion or poor connections at the module connectors
• Software issues or bugs within the vehicle’s control systems

DTC U1189 seriousness

DTC U1189 can be considered serious as it may indicate a communication failure between critical vehicle systems. This can lead to:

• Reduced vehicle performance
• Inability to access certain diagnostic data
• Potential safety concerns if critical systems are affected

How to diagnose DTC U1189

To diagnose DTC U1189, follow these steps:

1. Use an OBD-II scanner to confirm the presence of DTC U1189.
2. Check for any additional trouble codes 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 communication network using a multimeter.

How to fix DTC U1189 step-by-step instructions

To fix DTC U1189, follow these steps:

1. Repair or replace any damaged wiring or connectors in the SCP network.
2. Replace any faulty control modules identified during diagnosis.
3. Clean any corroded connections to ensure proper communication.
4. Update the software of the control modules if necessary.
5. Clear the DTC using an OBD-II scanner and test drive the vehicle to ensure the issue is resolved.

How to erase DTC U1189

To erase DTC U1189, follow these steps:

1. Connect an OBD-II scanner to the vehicle’s diagnostic port.
2. Access the trouble codes menu on the scanner.
3. Select the option to clear or erase trouble codes.
4. Confirm the action and wait for the scanner to complete the process.
5. Disconnect the scanner and perform a test drive to ensure the code does not return.

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.