U1223 – OBD-II DTC

OBD-II DTC U1223 – SCP (J1850) Invalid or Missing Data for Interior Lamps

DTC U1223 meaning

DTC U1223 refers to a diagnostic trouble code indicating that there is invalid or missing data related to the interior lamps in a vehicle. This code is part of the On-Board Diagnostics II (OBD-II) system and is specifically associated with the SCP (Serial Communication Protocol) using the J1850 communication standard. The code suggests that the vehicle’s control modules are unable to communicate properly regarding the status of the interior lighting system.

DTC U1223 symptoms

Common symptoms associated with DTC U1223 may include:

• Interior lamps not functioning as expected
• Dashboard warning lights illuminated
• Inconsistent operation of other electrical components
• Possible issues with other communication-related DTCs

DTC U1223 causes

Several factors can lead to the triggering of DTC U1223, including:

• Faulty interior lamp control module
• Wiring issues, such as shorts or open circuits
• Corroded or loose connectors
• Malfunctioning body control module (BCM)
• Software glitches in the vehicle’s control systems

DTC U1223 seriousness

The seriousness of DTC U1223 can vary. While it may not pose an immediate safety risk, it can lead to inconvenience due to malfunctioning interior lights. Additionally, if left unaddressed, it may indicate underlying issues with the vehicle’s electrical system that could affect other components.

How to diagnose DTC U1223

To diagnose DTC U1223, follow these steps:

1. Use an OBD-II scanner to confirm the presence of DTC U1223.
2. Check for any additional DTCs that may provide more context.
3. Inspect the vehicle’s wiring and connectors related to the interior lamps for damage or corrosion.
4. Test the interior lamp control module for proper operation.
5. Verify the functionality of the body control module (BCM).
6. Check for software updates or reprogramming needs for the vehicle’s control modules.

How to fix DTC U1223 step-by-step instructions

To fix DTC U1223, follow these steps:

1. Address any wiring issues found during diagnosis, such as repairing or replacing damaged wires.
2. Clean or replace corroded connectors to ensure proper electrical contact.
3. Replace the faulty interior lamp control module if it is determined to be defective.
4. Reprogram or update the body control module if necessary.
5. Clear the DTC using an OBD-II scanner and test the system to ensure the issue is resolved.

How to erase DTC U1223

To erase DTC U1223, follow these steps:

1. Connect an OBD-II scanner to the vehicle’s diagnostic port.
2. Turn the ignition key to the “On” position without starting the engine.
3. Access the DTC menu on the scanner and locate DTC U1223.
4. Select the option to clear or erase the trouble codes.
5. Turn off the ignition and disconnect the scanner.
6. Start the vehicle and monitor for any reoccurrence 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.