U0104 on Mercedes-Benz C-Class
Factory diagnostic protocol and troubleshooting wire for fault code U0104 specifically for the Mercedes-Benz C-Class (2020–2026, 2.0L Turbo 4-Cyl with 48V Mild Hybrid (M254 255HP) / AMG C 43 (402HP)).
1. Symptoms of U0104 on Mercedes-Benz C-Class
When the Engine Control Module (ECM/PCM) on your Mercedes-Benz C-Class (2.0L Turbo 4-Cyl with 48V Mild Hybrid (M254 255HP) / AMG C 43 (402HP)) logs fault code U0104, drivers commonly observe:
2. Most Likely Causes on Mercedes-Benz C-Class
Historical warranty claims and technical repair bulletins for Mercedes-Benz C-Class point to the following failure distribution:
3. Step-by-Step DIY Repair Guide for Mercedes-Benz C-Class
Clean snow, ice, mud, or dead bugs off front radar emblem. on the Mercedes-Benz C-Class equipped with 2.0L Turbo 4-Cyl with 48V Mild Hybrid (M254 255HP) / AMG C 43 (402HP).
Verify power feed to radar sensor. on the Mercedes-Benz C-Class equipped with 2.0L Turbo 4-Cyl with 48V Mild Hybrid (M254 255HP) / AMG C 43 (402HP).
Execute optical/radar alignment procedure if bumper was removed. on the Mercedes-Benz C-Class equipped with 2.0L Turbo 4-Cyl with 48V Mild Hybrid (M254 255HP) / AMG C 43 (402HP).
Clear DTCs and test cruise on highway. on the Mercedes-Benz C-Class equipped with 2.0L Turbo 4-Cyl with 48V Mild Hybrid (M254 255HP) / AMG C 43 (402HP).
Equipment for Diagnosing Mercedes-Benz C-Class (U0104)
Mercedes-Benz C-Class OEM Replacement Sensor
Direct-fit replacement assembly engineered to OEM tolerances for Mercedes-Benz C-Class.
AstroAI Auto-Ranging Digital Multimeter
Essential for testing 0.1V–5.0V sensor reference signals, ground continuity (<0.20Ω), and harness resistance.
BlueDriver Bluetooth Pro OBDII Scan Tool
Reads and clears enhanced codes (ABS, Airbag, Transmission, Engine) & live freeze-frame telemetry on phone.
Other Common Fault Codes on Mercedes-Benz C-Class
Frequently diagnosed powertrain, emissions, and sensor trouble codes logged on the Mercedes-Benz C-Class:
4. Mercedes-Benz C-Class U0104 FAQs
What causes code U0104 to trigger on a Mercedes-Benz C-Class?
On the Mercedes-Benz C-Class (2.0L Turbo 4-Cyl with 48V Mild Hybrid (M254 255HP) / AMG C 43 (402HP)), U0104 is most frequently caused by Blocked or dirty front radar sensor in grille/bumper or Blown radar module fuse.
Where is the OBD-II port located on my Mercedes-Benz C-Class?
On the Mercedes-Benz C-Class, the 16-pin DLC diagnostic connector is located Under driver dash beneath purple/black sliding protective door. Plug in any standard OBD-II scanner with the ignition in the ON position to read freeze-frame parameters.
Can I safely drive my Mercedes-Benz C-Class with code U0104?
Yes. Normal driving is unaffected, but Adaptive Cruise Control will not engage. Given that U0104 carries a Low severity rating, we advise avoiding heavy towing or aggressive throttle inputs until sensor readings are verified.