MERCEDES-BENZ · 2026-02-03
Complaint Check engine light illuminate, or previously on One of the below Exhaust Flap fault codes stored in PTCU N127: P13C273 P13C278 P140473 Cause Various Remedy Model year 2024 254 and 167 with engine M254 -Update software of N127 PTCU. New software: 254- A2549022611 167- A2549022811 -Clear fault codes and check operation of the exhaust flap. Models with M256, or models with M254 after SW update -Check exhaust flap for free movement via actuation. -Remove flap actuator and check movement of flap in exhaust pipe. Replace exhaust pipe section if flap is binding. -Replace flap actuator if above checks are ok. If fault code returns after performing the above steps, open a TIPS case with the powertrain team. Note: Codes P13C273 and P13C278- Right side flap Code P140473- Left side flap