P0457 on Mercedes-Benz C-Class
Factory diagnostic protocol and troubleshooting wire for fault code P0457 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 P0457 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 P0457, 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
Unscrew gas cap, inspect rubber seal for cracks, reinstall and turn until it clicks firmly 3 times. on the Mercedes-Benz C-Class equipped with 2.0L Turbo 4-Cyl with 48V Mild Hybrid (M254 255HP) / AMG C 43 (402HP).
Check the metal filler neck lip for rust, grit, or dings preventing a tight seal. on the Mercedes-Benz C-Class equipped with 2.0L Turbo 4-Cyl with 48V Mild Hybrid (M254 255HP) / AMG C 43 (402HP).
If rubber gasket is flattened or hardened, buy a factory OEM gas cap. 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 with scanner, or drive vehicle for 3–5 days until the PCM runs an overnight EVAP vacuum decay test and turns off the light automatically. 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 (P0457)
OEM Tethered Fuel Gas Cap with O-Ring
Tight-sealing factory fuel cap resolves common EVAP small/large leak codes without workshop visits.
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 P0457 FAQs
What causes code P0457 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)), P0457 is most frequently caused by Loose, unclicked, or forgotten gas cap or Cracked, dried out, or missing rubber O-ring gasket on fuel cap.
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 P0457?
Yes. Safe to drive indefinitely, but fuel vapors escape into the atmosphere. Given that P0457 carries a Low severity rating, we advise avoiding heavy towing or aggressive throttle inputs until sensor readings are verified.