2015 Mercedes-Benz C400 Technical Service Bulletins

116 technical service bulletins (TSBs) are on record for the 2015 Mercedes-Benz C400. TSBs are notes manufacturers send to dealers about repair procedures for issues seen in the field. They are not recalls and do not by themselves mean a vehicle has a fault.

• 11038186Sep 22, 2026Brakes. Complaint Repeat workshop visit for vehicle vibration while braking from 60MPH. NOTE: Although the symptom is similar to a tire or wheel vibration, it is usually readily noticeable that it is distinctly different if it happens at all times or only while braking. Cause Although the cause of the vibration is most likely due to excessive lateral runout on the rotor or hub/wheel bearing, the system as a whole needs to…
• 11038217Sep 14, 2026Body and structure. Complaint Clanking noise from the area of the speakers in the doors. Cause Under analysis. Remedy To narrow down the cause, first of all remove the door trim. • If the noise continues to occur even with the door trim removed, then continue the diagnosis working towards the speaker and if necessary, create a TIPS case with an informative video as an attachment.
• 11037228Aug 28, 2026Steering. Complaint During part of the steering movement, it feels heavier or more difficult to steer in the same spot every time. OR Rattling, humming, dry sliding/gravel noise from the electric steering system when steering (see attachment). Complaint does not impact the ability to safely steer or control the vehicle. Cause Ball screw drive (KGT) of electric steering damaged by: 1. External force due to: ‑ Hitting the…
• 11036511Aug 24, 2026Electrical system, Body and structure. Complaint Tailgate opens unintentionally. Cause Accidental or unnoticed activation of the button to open the tailgate on the vehicle key. EXAMPLE: when stored in trouser pocket, handbag etc. Remedy As of the 6th generation, the vehicle key can be recoded so that the tailgate no longer opens as a result of a long press on the button, but by double‑clicking on the button instead. This reduces the likelihood of the…
• 11036142Aug 12, 2026Electrical system. Complaint 1. General Diagnostic Tips 2. One or More PARK Sensor Activations 3. Red Ring Around Vehicle 4. "Active Parking and Parking Assist Inoperative" on Instrument Cluster 5. Cameras 6. Other Park Topics. Cause Various root causes Remedy See attached diagnostic guide.
• 11036190Aug 6, 2026Electrical system. Complaint A popup is seen on the HU with the message "data connection temporarily not available". Potentially affected functionalities in NTG4.5, NTG5 1.Weather 2.Local Search 3.IP Radio 4.Send2Car 5.Speech Detection Service 6.Navigation 7.iHeartRadio 8.Traffic Cams Cause MB Apps is sundowned for all vehicles with NTG4.5 and NTG5 Head Unit Variant. Remedy No support available for NTG4.5 and NTG5 Head Unit Variants…
• 11036101Aug 6, 2026Body and structure. Complaint Clanking noise from the area of the speakers in the doors. Cause Under analysis. Remedy To narrow down the cause, first of all remove the door trim. • If the noise continues to occur even with the door trim removed, then continue the diagnosis working towards the speaker and if necessary, create a TIPS case with an informative video as an attachment.
• 11035005Jul 14, 2026Transmission and drivetrain. Single throttle lift-off clunking noise from the side shaft when moving off (audible at the outboard end). The noise is heard once in each instance when changing direction of travel. Note: Sound file in attachment Cause If the complaint is eliminated by experimentally loosening the outboard collar nut (by 1 turn), the problem is due to cracking of the microweld between the wheel bearing inner race and the joint…
• 11034064Jun 19, 2026Visibility (wipers, defrost, mirrors), Engine. Dear Mercedes-Benz USA Dealers, The part numbers listed in the chart below should no longer be installed, and any existing stock must be returned to your facing PDC. The deadline for all dealer returns is no later than Thursday, July 9, 2026. After July 9th, returns of these parts will no longer be accepted. These parts should be returned via ZSR Special Return, using item category SCM Authorized Part Return…
• 11033855Jun 12, 2026Electrical system. Complaint Service code B1 displayed in the customer menu does not match the workshop code displayed in the workshop menu, e.g., 505 or 550A, which includes a service A. Cause The root cause is currently being investigated. Remedy To determine the cause, the instrument cluster control unit (N133/1) and powertrain control unit (N127) logs are required before confirming the service or correction using XENTRY Diagnosis.
• 11033185May 26, 2026Electrical system. Complaint After successful commissioning of the HERMES control unit (N112/9) with XENTRY Diagnosis DVD 03/2026, the message "SOS - service not activated" appears on the instrument cluster.
• 11033016May 26, 2026Electrical system. Complaint The customer requests deactivation of the N112/9 HERMES communication module Note: Deactivation of the HERMES control unit (N112/9) is not supported for gray-market vehicles. Cause Before deactivating the HERMES control unit (N112/9), it must be clarified by the legal department of the respective MPC whether and under what conditions deactivation may be carried out. If deactivation is not permissible…
• 11032875May 19, 2026Visibility (wipers, defrost, mirrors). Complaint There are several types of complaint about noises or poor windshield wiper wiping performance: A: Wiper blades squeaking, chattering, shuddering B: The windshield is not wiped completely (streaking) C: During the downward movement water is pulled back onto the windshield from the A-pillar (Figure 1) D: After windshield cleaning, water keeps spraying onto the windshield for several wipe cycles (Figure 2)…
• 11032699May 12, 2026Back-over prevention (rear camera), Lane departure, Electrical system. Complaint 1. General Diagnostic Tips 2. One or More PARK Sensor Activations 3. Red Ring Around Vehicle 4. "Active Parking and Parking Assist Inoperative" on Instrument Cluster 5. Cameras 6. Other Park Topics Cause Various root causes Remedy See attached diagnostic guide.
• 11031580Apr 16, 2026Exterior lighting. Complaint Headlamp, front fog lamp leaky or fogged. Cause Fogging of the headlamps is a natural phenomenon, which can occur under certain climatic conditions. It does not lead to any technical impairment of the headlamp. If a pressure compensation diaphragm is fitted in the housing cover, then the lamp unit is a "closed system". Remedy Headlamp: Remedy 1 Clearing fogged/condensed LED headlamps: 1.
• 11030088Mar 9, 2026Electrical system. Complaint 1. General Diagnostic Tips 2. One or More PARK Sensor Activations 3. Red Ring Around Vehicle 4. "Active Parking and Parking Assist Inoperative" on Instrument Cluster 5. Cameras 6. Other Park Topics Cause Various root causes Remedy See attached diagnostic guide.
• 11029959Mar 9, 2026Exterior lighting. Complaint Headlamp, front fog lamp leaky or fogged Cause Fogging of the headlamps is a natural phenomenon, which can occur under certain climatic conditions. It does not lead to any technical impairment of the headlamp. If a pressure compensation diaphragm is fitted in the housing cover, then the lamp unit is a "closed system". Remedy Headlamp: Remedy 1 Clearing fogged/condensed LED headlamps: 1.
• 11029025Feb 24, 2026Exterior lighting. Complaint Headlamp, front fog lamp leaky or fogged Cause Fogging of the headlamps is a natural phenomenon, which can occur under certain climatic conditions. It does not lead to any technical impairment of the headlamp. If a pressure compensation diaphragm is fitted in the housing cover, then the lamp unit is a "closed system". Remedy Headlamp: Remedy 1 Clearing fogged/condensed LED headlamps: 1.
• 11028816Feb 13, 2026Electrical system. Complaint 1. General Diagnostic Tips 2. One or More PARK Sensor Activations 3. Red Ring Around Vehicle 4. "Active Parking and Parking Assist Inoperative" on Instrument Cluster 5. Cameras 6. Other Park Topics Cause Various root causes Remedy See attached diagnostic guide.
• 11028809Feb 13, 2026Other or unknown. Mercedes-Benz AG, the manufacturer of Mercedes-Benz vehicles, has determined that on certain subject vehicles, the TIREFIT sealant bottle may not meet specifications. The possibility exists that the sealant bottle may leak or may have otherwise been removed from the vehicle. MBUSA will conduct a service campaign. An authorized Mercedes-Benz dealer will replace the TIREFIT bottle in the trunk.
• 11027904Jan 30, 2026Electrical system, Back-over prevention (rear camera). Complaint 1. General Diagnostic Tips 2. One or More PARK Sensor Activations 3. Red Ring Around Vehicle 4. "Active Parking and Parking Assist Inoperative" on Instrument Cluster 5. Cameras 6. Other Park Topics Cause Various root causes Remedy See attached diagnostic guide.
• 11027751Jan 16, 2026Visibility (wipers, defrost, mirrors). Complaint Customer states the AC either does not cool/has poor performance or heat is insufficient. Cause Many possible root causes Remedy *Note - This Li does not apply if there are other Li's that apply to your concern OR you have a fault and/or guided test that leads to a root cause. AC Diagnosis (General) Initial Steps Verify Customer Concern • Confirm the issue reported by the customer. Compare to Like Vehicle…
• 11027682Jan 15, 2026Visibility (wipers, defrost, mirrors). Complaint Customer states the AC either does not cool/has poor performance or heat is insufficient. Cause Many possible root causes Remedy AC Diagnosis (General) Initial Steps Verify Customer Concern • Confirm the issue reported by the customer. Compare to Like Vehicle • Determine if the behavior is normal by comparing with a similar vehicle. Determine Your Game and Players • Identify the diagnostic strategy and…
• 11027566Jan 7, 2026Visibility (wipers, defrost, mirrors). Complaint Customer states the AC either does not cool/has poor performance or heat is insufficient. Cause Many possible root causes Remedy AC Diagnosis (General) Initial Steps Verify Customer Concern • Confirm the issue reported by the customer. Compare to Like Vehicle • Determine if the behavior is normal by comparing with a similar vehicle. Determine Your Game and Players • Identify the diagnostic strategy and…
• 11026835Dec 18, 2025Electrical system. Complaint The flap of the reversing camera opens and closes by itself during forward travel several times during the trip. No camera image is displayed in the head unit. The reversing camera or the 360° system functions normally when activated manually or by engaging drive range "R". Cause This is not a malfunction, but an intended system behavior. Calibration of the reversing camera is in progress.
• 11026611Dec 11, 2025Electrical system. Complaint 1. General Diagnostic Tips 2. One or More PARK Sensor Activations 3. Red Ring Around Vehicle 4. "Active Parking and Parking Assist Inoperative" on Instrument Cluster 5. Cameras 6. Other Park Topics Cause Various root causes Remedy See attached diagnostic guide.
• 11025560Nov 17, 2025Transmission and drivetrain. Complaint The shift from 1st to 2nd gear may be uncomfortable under light load. Cause Vehicles with engine M264 and transmission 725.0 may be equipped with specific software versions. Remedy Update Transmission Software (VGSNAG3). 1.
• 11025648Nov 15, 2025Transmission and drivetrain. Complaint Single throttle lift-off clunking noise from the side shaft when moving off (audible at the outboard end). The clunk is heard once when changing from forward to reverse (and vice versa). Note: Sound file in attachment Cause If the complaint is eliminated by experimentally loosening the outboard collar nut (by 1 turn), the problem is due to micromovement in the connection between the wheel bearing inner…
• 11023193Sep 17, 2025Transmission and drivetrain. Complaint Transmission control unit Y3/8n4 (fully integrated transmission control unit (VGS)) not listed in quick test and/or no communication possible with VGS. Cause Transmission control unit Y3/8n4 Remedy For vehicles with 722.9 transmission: Ensure LI54.15-P-057373 is performed before replacing any component parts. After processing and complying with the above document(s): 1. Perform an ignition reset on Y3/8n4…
• 11018626May 22, 2025Electrical system. Complaint After a software update of HERMES communication module N112/9 has been performed on a gray import vehicle, the message "SOS - Service not activated" is displayed in the instrument cluster. Cause The message "SOS - Service not activated" tells the customer that "over-the-air" registration of the vehicle with the Mercedes Intelligent Cloud is not possible.
• 11019018May 21, 2025Transmission and drivetrain. Complaint Single throttle lift-off clunking noise from the side shaft when moving off (audible at the outboard end). The clunk is heard once when changing from forward to reverse (and vice versa). Note: Sound file in attachment Cause If the complaint is eliminated by experimentally loosening the outboard collar nut (by 1 turn), the problem is due to micromovement in the connection between the wheel bearing inner…
• 11018206May 2, 2025Electrical system. Complaint The result from the XENTRY battery test does not match the current state of the battery. Cause The XENTRY battery tester uses the stored on-board electrical system data in the SAM module to access the health of the 12 volt battery. The XENTRY battery test may not take into account a single discharge event because the SAM or EZS cannot record the data if the battery is discharged. Note: A discharged…
• 11017500Apr 28, 2025Exterior lighting. Complaint Headlamps leaking or fogged Cause The fogging of the headlamp is a natural phenomenon which can occur under certain climatic conditions. In contrast to a leaky headlamp, physical fogging does not result in a technical impairment of the headlamp. A leak test must be performed to determine if physical fogging exists or if the headlamp is leaky. Remedy Check for external damage: You can identify a damaged…
• 11017496Apr 28, 2025Exterior lighting. Complaint Headlamp, front fog lamp leaky or fogged Cause Fogging of the headlamps is a natural phenomenon, which can occur under certain climatic conditions. It does not lead to any technical impairment of the headlamp. Remedy NOTE: If a pressure compensation diaphragm is fitted in the housing cover, then the lamp unit is a "closed system". Headlamp: Remedy 1 Clearing fogged/condensed LED headlamps and LED rear…
• 11017119Apr 21, 2025Electrical system. Complaint A popup is seen on the HU with the message "data connection temporarily not available". Potentially affected functionalities in NTG4.5, NTG5 1.Weather 2.Local Search 3.IP Radio 4.Send2Car 5.Speech Detection Service 6.E-Navigator 7.iHeartRadio 8.Traffic Cams Cause Analysis ongoing. Remedy Please track the LI for further updates. Note: Please do not create TIPS cases. Please do not replace any components…
• 11015574Mar 11, 2025Exterior lighting. Complaint The message "Device detected at diagnostics connection See Owner’s Manual" appears sporadically in the multifunction display of the instrument cluster while driving (see picture in attachment).
• 11015640Mar 5, 2025Electrical system. Complaint During a phone call, the called party has difficulty understanding/cannot understand the driver, or interference/background noises are audible to the called party during a call. It becomes increasingly difficult to understand as the speed rises. Cause A. Seating of the microphones in the headliner. Side edges are covered by the textile cover (see picture "1") B. Assembly of microphones (B25/20 or B25/21)…
• 11014608Feb 24, 2025Electrical system, Back-over prevention (rear camera). Complaint The flap of the reversing camera opens and closes by itself during forward travel several times during the trip. No camera image is displayed in the head unit. The reversing camera or the 360° system functions normally when activated manually or by engaging drive range "R". Cause This is not a malfunction, but an intended system behavior. Calibration of the reversing camera is in progress.
• 11014576Feb 24, 2025Electrical system. Complaint The flap of the reversing camera opens and closes by itself during forward travel several times during the trip. No camera image is displayed in the head unit. The reversing camera or the 360° system functions normally when activated manually or by engaging drive range "R". Cause This is not a malfunction, but an intended system behavior. Calibration of the reversing camera is in progress.
• 11014402Feb 21, 2025Fuel system. Complaint Customer-perceived problem: • Fuel gauge reading implausible • MIL ON (market-dependent) N118/3 Fault codes in control units FSCM_GEN4/5/6 • For these fault codes, the tests contained in XENTRY must be carried out P046109 / P206609 / P13E600 • For these fault codes, the connector couplings/wiring harness routing must be checked for damage P206600 / P046100 Cause Various Remedy Carry out XENTRY tests for…
• 11013192Jan 24, 2025Body and structure. Complaint Fuel door may require several attempts to open. Please note that if the complaint "Fuel filler flap not opening" occurs, it is important to check the fuel filler flap before replacing the central locking actuator. For gasoline hybrid vehicles where the fuel filler flap fails to open or does so but slowly, observe the document "Fuel filler flap fails to open or does so but slowly on plug-in HYBRID gasoline…
• 11013185Jan 24, 2025Body and structure. Complaint Paint damage on door paneling in area of door handle (see picture 1). Cause Alignment of door handle bearing bracket is not correct. Remedy 1. Paint the affected area of the door paneling using the spot repair procedure in accordance with the manufacturer's specifications. 2. Replace the door handle, ensuring that the door handle bearing bracket is installed correctly (see picture 2). Note: The optimized…
• 11013184Jan 24, 2025Body and structure. Complaint Noise from area of instrument panel Noise might occur in the following conditions: - At engine speeds of 1500 rpm to 2000 rpm. - In the speed range up to 45mph - Type of noise: "rattling" / "whirring" / "creaking" Cause Attachment points between strut on shock absorber tower and firewall. Remedy Proceed as described below: 1. Measure the current torque at the rear screws/bolts (strut to bulkhead) and…
• 11013179Jan 24, 2025Fuel system. Complaint Customer-perceived problem: • Fuel gauge reading implausible • MIL ON (market-dependent) N118/3 Fault codes in control units FSCM_GEN4/5/6 • For these fault codes, the tests contained in XENTRY must be carried out P046109 / P206609 / P13E600 • For these fault codes, the connector couplings/wiring harness routing must be checked for damage P206600 / P046100 Cause Various Remedy Carry out XENTRY tests for…
• 11013347Jan 23, 2025Body and structure. Complaint Wind or airflow noises in the area of the doors Cause Airflow noises or tire noise. The noises entering the interior may be perceived as too loud. Remedy MODEL 205/0/1/2 1. Check door adjustment. Also check the transition from the doors to the A-pillar, see Figure 1, and correct if necessary by adjusting the doors in the y-direction. 2. Check outside mirror cover for parallelism and correct seating, see…
• 11013298Jan 16, 2025Transmission and drivetrain. Complaint Single throttle lift-off clunking noise from the side shaft when moving off (audible at the outboard end). The clunk is heard once when changing from forward to reverse (and vice versa). Cause If the complaint is eliminated by experimentally loosening the outboard collar nut (by 1 turn), the problem is due to micromovement in the connection between the wheel bearing inner race and the joint housing of the…
• 11013332Jan 15, 2025Transmission and drivetrain. Complaint Single throttle lift-off clunking noise from the side shaft when moving off (audible at the outboard end). The noise is heard once in each instance when changing direction of travel. Note: Sound file in attachment Cause If the complaint is eliminated by experimentally loosening the outboard collar nut (by 1 turn), the problem is due to cracking of the microweld between the wheel bearing inner race and the…
• 11013086Jan 15, 2025Electrical system. Complaint The flap of the reversing camera opens and closes by itself during forward travel several times during the trip. No camera image is displayed in the head unit. The reversing camera or the 360° system functions normally when activated manually or by engaging drive range "R". Cause This is not a malfunction, but an intended system behavior. Calibration of the reversing camera is in progress.
• 11010907Nov 25, 2024Electrical system. Complaint The flap of the reversing camera opens and closes by itself during forward travel. This happens several times during the trip. The customer notices the sound of opening and closing. No camera image is displayed in the head unit. The reversing camera or the 360° system functions normally when activated manually or by engaging drive range "R". This behavior occurs again during each driving cycle.
• 11010818Nov 20, 2024Transmission and drivetrain. Complaint Transmission control unit Y3/8n4 (fully integrated transmission control unit (VGS)) not listed in quick test and/or no communication possible with VGS. Cause Transmission control unit Y3/8n4 Remedy It is important that LI54.15-P-057373 is processed before replacing any component parts (transmission 722.9).

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