U1242 – OBD-II DTC

OBD-II DTC U1242 – SCP (J1850) Invalid or Missing Data for Exterior Environment

DTC U1242 meaning

DTC U1242 refers to a diagnostic trouble code that indicates an issue with the communication between the vehicle’s modules regarding the exterior environment data. Specifically, it signifies that the data from the Serial Communication Protocol (SCP) using the J1850 standard is either invalid or missing. This can affect various systems that rely on accurate environmental data, such as climate control and safety features.

DTC U1242 symptoms

Common symptoms associated with DTC U1242 may include:

• Malfunctioning climate control systems
• Inaccurate readings on exterior temperature displays
• Warning lights illuminated on the dashboard
• Potential issues with other modules that rely on exterior environment data

DTC U1242 causes

Several factors can lead to the occurrence of DTC U1242, including:

• Faulty or damaged wiring in the SCP network
• Defective exterior temperature sensor
• Issues with the vehicle’s control modules
• Corrosion or poor connections in the communication network
• Software glitches or programming errors in the vehicle’s modules

DTC U1242 seriousness

The seriousness of DTC U1242 can vary depending on the vehicle’s reliance on the affected systems. While it may not pose an immediate safety risk, it can lead to:

• Inaccurate climate control settings
• Reduced functionality of other systems that depend on environmental data
• Potential for further diagnostic trouble codes to arise if left unaddressed

How to diagnose DTC U1242

To diagnose DTC U1242, follow these steps:

1. Use an OBD-II scanner to confirm the presence of DTC U1242.
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 exterior temperature sensor for proper operation.
5. Examine the control modules for any software updates or faults.
6. Perform a visual inspection of the vehicle’s communication network.

How to fix DTC U1242 step-by-step instructions

To fix DTC U1242, follow these steps:

1. Repair or replace any damaged wiring or connectors in the SCP network.
2. Replace the exterior temperature sensor if it is found to be faulty.
3. Clear any corrosion from connectors and ensure secure connections.
4. Update the software in the vehicle’s control modules if necessary.
5. Re-scan the vehicle with the OBD-II scanner to check if the code reappears.

How to erase DTC U1242

To erase DTC U1242, 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 take the vehicle for 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.