The diagnostic trouble code C426 typically relates to issues with the Tire Pressure Monitoring System (TPMS) in Mercedes-Benz vehicles.

The diagnostic trouble code C426 typically relates to issues with the Tire Pressure Monitoring System (TPMS) in Mercedes-Benz vehicles. More specifically, it often indicates a communication problem or fault within the TPMS system. Here are some steps to address this code:

1. **Retrieve Additional Information:** To get a more precise understanding of the issue, use a Mercedes-Benz-specific diagnostic tool or an OBD-II scanner capable of reading manufacturer-specific codes to retrieve additional information associated with C426.

2. **Check TPMS Sensors:** The TPMS relies on sensors within each tire to monitor tire pressure. Ensure that all TPMS sensors are properly installed and functioning correctly. If a sensor is damaged or not transmitting data, it may need to be replaced.

3. **Check Sensor Batteries:** Some TPMS sensors have batteries that may need replacement over time. If the sensor batteries are depleted, the sensors may not function correctly. Replace the sensor batteries as needed.

4. **Inspect Wiring and Connectors:** Inspect the wiring and connectors associated with the TPMS system for damage, corrosion, or loose connections. Faulty wiring can lead to communication issues.

5. **Verify Tire Pressure:** Make sure that the tire pressure in all four tires is at the recommended level specified in your vehicle's owner's manual. Incorrect tire pressure can trigger TPMS warnings.

6. **Reset TPMS:** After addressing any issues, you can try resetting the TPMS system using the appropriate procedure in your vehicle's owner's manual or through the TPMS reset function in your vehicle's settings.

7. **Clear Fault Codes:** Use your diagnostic tool to clear the C426 fault code. After addressing the underlying issue, the code should no longer appear.

8. **Professional Assistance:** If you are unable to diagnose or resolve the issue on your own, or if the problem persists after inspection and basic maintenance, it's advisable to seek assistance from a qualified Mercedes-Benz technician or mechanic. They have the specialized knowledge and equipment needed for in-depth TPMS diagnostics and repairs.

Please note that the specific steps and procedures may vary depending on your Mercedes-Benz model and year. Always consult your vehicle's service manual or repair documentation for model-specific guidance. Additionally, working with vehicle electronics can be complex, so if you're unsure about any aspect of the diagnosis or repair, it's best to consult with a professional to ensure the proper functioning of the TPMS system.