2021 Mercedes-Benz C300 technical service bulletins
178 technical service bulletins and manufacturer communications cover the 2021 Mercedes-Benz C300, including 4 warranty extensions.
Bulletins tell dealers how to fix known problems. A warranty extension means the manufacturer pays for that repair for longer.
- Dear Mercedes-Benz Owner: In our continuing efforts to ensure the proper performance of Mercedes-Benz...
- Fuel/propulsion system
- In our continuing efforts to ensure the proper performance of Mercedes-Benz products and to enhance the...
- In our continuing efforts to ensure the proper performance of Mercedes-Benz products and to enhance the...
- Customer complaints relating to automatic transmission 725.0 (NAG3 Classic /9G‑TRONIC automatic...
- Slight creaking noises when steering
- Repeat workshop visit for vehicle vibration while braking from 60MPH. NOTE: Although the symptom is...
- Only vehicles with a variable transfer case are affected
- Clanking noise from the area of the speakers in the doors
- Customer complaints relating to automatic transmission 725.0 (NAG3 Classic / 9G‑TRONIC automatic...
- During part of the steering movement, it feels heavier or more difficult to steer in the same spot every time
- • Harsh 1‑2, 2‑3, and/or 3‑4 shift • Jerky shifting • Jolting when accelerating from stop
- Tailgate opens unintentionally
- 1. General Diagnostic Tips 2. One or More PARK Sensor Activations 3. Red Ring Around Vehicle 4. "Active...
- A popup is seen on the HU with the message "data connection temporarily not available". Potentially...
- This document is intended as a pre-case diagnostic reference for transmission related concerns
- Mercedes-Benz USA is currently experiencing limited availability of transmission fluid specification ATF...
- Engine
- Single throttle lift-off clunking noise from the side shaft when moving off (audible at the outboard end)
- Dear Mercedes-Benz USA Dealers, The part numbers listed in the chart below should no longer be installed,...
- Service code B1 displayed in the customer menu does not match the workshop code displayed in the workshop...
- After successful commissioning of the HERMES control unit (N112/9) with XENTRY Diagnosis DVD 03/2026, the...
- Dear Mercedes-Benz USA Dealers, The part numbers listed in the chart below should no longer be installed,...
- There are several types of complaint about noises or poor windshield wiper wiping performance: A: Wiper...
- The part numbers listed in the chart below should no longer be installed, and any existing stock must be...
- 1. General Diagnostic Tips 2. One or More PARK Sensor Activations 3. Red Ring Around Vehicle 4. "Active...
- Damaged cords/tensioning cables at the soft top interior trim with the following characteristics
- Headlamp, front fog lamp leaky or fogged
- -Check engine light illuminated
- Yellow information message in driver display (instrument cluster): "Switch on motor to charge the 12V battery"
- Headlamp, front fog lamp leaky or fogged
- Engine
- Unknown or other
- Check engine light on with the following fault is current in the VGS Control Unit: P084300 Oil pressure...
- The vehicle cannot disengage “P” (Park), and a red warning message appears in the instrument cluster
- Dear Mercedes-Benz Owner: In our continuing efforts to ensure the proper performance of Mercedes-Benz...
- Customer states the AC either does not cool/has poor performance or heat is insufficient
- (Original LI document #: LI27.35-P-079039) Clicking noises from the electro-hydraulic control unit (EHS)...
- The flap of the reversing camera opens and closes by itself during forward travel several times during the...
- The shift from 1st to 2nd gear may be uncomfortable under light load
- Single throttle lift-off clunking noise from the side shaft when moving off (audible at the outboard end)
- Possible complaints about shift quality, issues with learning the park lock, and slipping/rinse entries in...
- The result from the XENTRY battery test does not match the current state of the battery
- Mercedes-Benz AG, the manufacturer of Mercedes-Benz vehicles, has updated driver assistance system...
- Electrical system
- Complaint
- Mercedes-Benz AG, the manufacturer of Mercedes-Benz vehicles, has updated driver assistance system SCN...
- Height adjustment of electric steering column adjustment jammed in the top/bottom adjustment position...
- The following most common complaints may be observed: • Brief connectivity interruptions when using Apple...
- In our continuing efforts to ensure the proper performance of Mercedes-Benz products and to enhance the...
- After a software update of HERMES communication module N112/9 has been performed on a gray import vehicle,...
- Electrical system
- Headlamp, front fog lamp leaky or fogged
- Headlamps leaking or fogged
- A popup is seen on the HU with the message "data connection temporarily not available". Potentially...
- A clicking/ticking/taping noise from underneath the vehicle with engine off during ECO stop event or after...
- The message "Device detected at diagnostics connection See Owner’s Manual" appears sporadically in the...
- Electrical system
- During a phone call, the called party has difficulty understanding/cannot understand the driver, or...
- The flap of the reversing camera opens and closes by itself during forward travel several times during the...
- Customer-perceived problem: • Fuel gauge reading implausible • MIL ON (market-dependent) N118/3 Fault...
- Electrical system
- Electrical system
- Noise from area of instrument panel Noise might occur in the following conditions
- Fuel door may require several attempts to open
- Single throttle lift-off clunking noise from the side shaft when moving off (audible at the outboard end)
- Single throttle lift-off clunking noise from the side shaft when moving off (audible at the outboard end)
- Electrical system
- Electrical system
- The flap of the reversing camera opens and closes by itself during forward travel
- After a control unit replacement of "N112/9
- Transmission control unit Y3/8n4 (fully integrated transmission control unit (VGS)) not listed in quick...
- Rear lamps fogged up/not leaktight
- Only vehicles with a variable transfer case are affected
- Washer fluid system leaks
- Check engine light on. One of the below fault codes is current in the engine control module (N3/10)
- Tension-releasing impact of the propeller shaft with the force-free in D "KID" function, after vehicle has...
- Check engine light on. Fault code P207273
- Headlamp or front fog lamp leaky or fogged
- Headlamps fogged or droplets forming
- To insure vehicle down time is kept at a minimum and all required information is available when case is...
- Headlamps fogged or droplets forming
- Electrical system
- Yellow Coolant warning comes on in cluster Fault codes below are current or stored in MED41 P0A0500- The...
- Check engine light on and fault code P019185 current or stored in MED41 control unit
- Customer complaints relating to automatic transmission 725.0 (NAG3 Classic / 9G-TRONIC automatic...
- Complaints about shift quality in vehicles of MODEL 205, 212 and 222 with TRANSMISSION 724.2.
- Noticeable vibrations at the steering wheel: • At speeds between 40mph and 75mph • On straight stretches...
- The driver's seat memory settings do not synchronize with the driver's user profile as described in the...
- Electrical system
- This is to notify you of the Service Campaign OTA update for the MBUX control unit software in 14,559...
- Tailgate opens unintentionally
- Electrical system
- Electrical system: software
- The steering wheel generates grinding noises between the steering wheel and steering column switch module...
- Noises in the steering column area when steering
- Electrical system
- Electrical system
- Electrical system
- Crease formation on genuine leather seat covers in vehicles with low mileage ⢠Objects left on the seats...
- Electrical system
- Electrical system
- Fault code P06DA00 is found current or stored in engine control unit
- Mercedes me connect services inoperative (me-Call, Remote Status, etc.). Mercedes me services
- Electrical system
- Wheezing noises from the front shock absorbers when passing over surface undulations and rough road
- The "SOS nonfunctional" message appears sporadically in the instrument cluster of the vehicle
- Electrical system
- Engine and engine cooling
- Electrical system
- Visibility
- Loads induced at the steering wheel through pushing and pulling actions may
- Tailgate opens unintentionally
- Staining on door trim strips and top and bottom trim elements on rear side windows
- Height adjustment of electric steering column adjustment jammed in the top/bottom adjustment position...
- Height adjustment of electric steering column adjustment jammed in the top/bottom adjustment position...
- Thumping noise on rear axle shock absorber on rough road
- Equipment
- Customer may have one or more of the following complaints: • Vehicle location is shown incorrectly in the...
- Electrical system
- Equipment: other: owners/service/other manual
- The touchpad dimming function does not work and the search lighting is either at maximum brightness or...
- The garage door hand transmitter cannot be initialized with the integrated garage door opener in the...
- The range of the integrated garage door opener (GTO) is too short
- Seat heating on driver's seat and front passenger seat nonfunctional
- MY15+ M278 and M157 Equipped Vehicles with Fault Code ""P023400 – Boost Pressure is Too High"" "
- Eco start/stop nonfunctional due to 12V battery
- The Weather App will not populate local weather data based on current vehicle position.
- Fuel filler flap opens slowly/switch flashes/tank is bleeding instrument cluster warning
- Intermittently after bus sleep the lower control panel LCP and upper control panel UCP may be panel UCP...
- Launch NCU
- Touch pad: Search lighting does not dim or does not turn on.
- Remote start causing CEL and U012600.
- With engine M17x the ME Control Unit: "The Coolant Temperature is Below the Specified Temperature"
- Message (yellow) in IC "Active Brake Assist currently restricted, see operator's manual, Remedy:...
- Engine switches off again when re-attempting Remote Start via Mercedes me App. This only occurs if the...
- Steering wheel heater and/or Distronic cannot be activated
- After ignition ON, the following message is shown on the instrument cluster
- Fault in 12 V interlock circuit
- When ordering the electrohydraulic controller unit (EHS) using the part number stated on the EHS, the...
- If the exhaust flap is operated or the drive program is changed within 10 seconds of the engine being...
- Air Conditioning Intermittently Does Not Cool
- NTG5.5
- Disturbed Antenna Signal.
- Navigation system permanently displays "Activating".
- Map pocket on front seat backrest trim does not close.
- Reset the customer-specific data and perform a software update of the AUDIO20 control unit.
- Intial startup not possible after replacement of transmisson 725.0 or of electrohydraulic controller unit.
- Headlamp fog.
- Traffic information service and posibly the voice control, nonfunctional after navigation software update.
- Cd/dvd
- High voltage battery warning message in instrument cluster.
- Gasket may settle causing a slight oil leak.
- Window lifter and outside mirror on passenger side malfunction after replacement of door control unit.
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