Check engine light, Exhaust flap fault
code P13C273, P13C278 or P140473
Topic number

LI49.10-P-080201

Version

1

Function group

49.10 - Exhaust pipes, mufflers

Date

2/2/26

Validity

Models 167, 214, 236, 254 with engines M254 or M256
Model years 2024-2025

Reason for change

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.
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© Copyright Mercedes-Benz AG

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-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

WIS-References
Document number

Title

Note

AR49.10-P-5507WTX

Remove/install exhaust gas flap controller

Models 214, 236, 254

AR49.10-P-5507MRX

Remove/install exhaust gas flap controller

Model 167

Disclaimer
NOTE: The information contained in this document is intended for use by trained, professional technicians with the
knowledge to properly and safely perform diagnosis and repairs on Mercedes-Benz vehicles, using Mercedes-Benz
approved tools and equipment. It informs service technicians about conditions that could occur in certain vehicles and
provides information that could assist in proper vehicle diagnosis, service, or repair. It does not indicate that a defect
is present in any vehicle referenced in this document nor does it imply warranty coverage. DO NOT assume that a
symptom or condition, or a described cause of a symptom or condition, affects any particular vehicle or groups of vehicles, or that a described repair applies to any particular vehicle or groups of vehicles. There can be multiple causes
resulting in the same or similar symptoms or conditions described in this document, and trained professional service
technicians must use their diagnostic skills to make evaluations on a case-by-case basis. The information contained
in this document does not guarantee warranty coverage nor does it extend the vehicle’s warranty in any way.

Symptoms
Power generation > Engine management > Indicator lamp > Engine diagnosis > lit

Control unit/fault code
Control unit

Fault text

N127 - Control unit "Drivetrain" (PTCU) (CPC3)

P140473 - Exhaust flap 2 has a malfunction. The actuator
does not open.
P13C278 - The exhaust flap 1 has a malfunction. The adaptation or adjustment is incorrect.
P13C273 - The exhaust flap 1 has a malfunction. The actuator does not open.

Operation numbers/damage codes
Op. no.

Operation text

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© Copyright Mercedes-Benz AG

Time

CCUSHWA

Damage
code

Note

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