2021 Mercedes-Benz G 550 Technical Service Bulletins

132 technical service bulletins (TSBs) are on record for the 2021 Mercedes-Benz G 550. 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.

• 11038187Sep 26, 2026Transmission and drivetrain. Complaint Customer complaints relating to automatic transmission 725.0 (NAG3 Classic /9G‑TRONIC automatic transmission) and 725.1 (NAG3 facelift/9G‑TRONIC automatic transmission facelift) For faster, more effective and more targeted diagnosis, Intelligent Predictive Repair (IPR) has been developed and integrated into XENTRY Diagnosis. This ensures an automated diagnosis process.
• 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.
• 11037987Sep 14, 2026Transmission and drivetrain. Complaint Only vehicles with a variable transfer case are affected. This can be identified through control unit N45 or N15/7 in the quick test. When accelerating with light load, vibrations or jolting sensation may come from the drivetrain. It may be mistaken for a harsh shift. Cause Modified oil quality of the transfer case over time Remedy 1. Check initial quick test for faults in the following control units.
• 11037616Sep 4, 2026Transmission and drivetrain. Complaint Customer complaints relating to automatic transmission 725.0 (NAG3 Classic / 9G‑TRONIC automatic transmission) and 725.1 (NAG3 facelift/9G‑TRONIC automatic transmission facelift) For faster, more effective and more targeted diagnosis, Intelligent Predictive Repair (IPR) has been developed and integrated into XENTRY Diagnosis. This ensures an automated diagnosis process.
• 11036607Aug 26, 2026Back-over prevention (rear camera), Forward collision avoidance. Complaint Consistently reproducible erroneous parktronic warnings from front with every key cycle. Cause The parking sensors are detecting the front brush guard. Remedy Complaint must be consistently reproducible and can occur multiple times a key cycle without obvious cause. NOTE: The parking system serves solely as an aid. Please review both the system function and system limitations as shown in the Operator's…
• 11036999Aug 15, 2026Fuel system. Dear Mercedes-Benz Owner: In our continuing efforts to ensure the proper performance of Mercedes-Benz products and to enhance the satisfaction of our customers, Mercedes-Benz USA is extending the warranty coverage for the Diagnostic Module for Tank Leakage Detection ("DMTL") on your vehicle from the original New Vehicle Limited Warranty of 4 years / 50,000 miles to 15 years/150,000 miles (whichever occurs first)…
• 11036229Aug 12, 2026Engine. Complaint Oil leaks found on M176 or M177 engines diagnosed to be from the cylinder head cover area Cause Unknown (under investigation) Remedy If oil leaks are found at left or right cylinder head cover area please collect the following information and open TIPS case. 1. Collect photos of the leak 2. Include close up and wide view photos to accurately represent the location 3. Include if the vehicle has a "check…
• 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.
• 11036077Aug 5, 2026Transmission and drivetrain. Complaint This document is intended as a pre-case diagnostic reference for transmission related concerns. It will also ensure that if a case is necessary, all supporting documentation is available. This should not be used on its own as justification for creating a TIPS case. Cause The root cause will vary depending on the complaint. The goal of this document is to provide diagnostic checks and procedures that may…
• 11035780Aug 4, 2026Other or unknown, Transmission and drivetrain. Complaint Mercedes-Benz USA is currently experiencing limited availability of transmission fluid specification ATF 236.17 due to a global supply constraint. 236.17 ATF 1L and 5L (PNs: A002989060312 and A002989060313) bottles are out of stock or in limited supply at Zep. This LI has been created with the following intention: - Provide dealers with additional workshop-focused guidance regarding the current ATF 236.17…
• 11035490Jul 31, 2026Fuel system. This NCU replaces the prior NCU issued on May 15, 2025, and contains additional MY 2023 and MY 2024 vehicles which are highlighted below.
• 11035238Jul 24, 2026Engine. Mercedes-Benz AG (“MBAG”), the manufacturer of Mercedes-Benz, has determined that on certain MY 2019-2021 C-Class, G-Class, GLC, GT, S-Class (205, 463, 253, 190 & 222 platforms) vehicles, the engine control unit software does not correspond to current production specifications. It is therefore possible that on-board diagnostics and/or exhaust gas emissions requirements may not be fulfilled.
• 11035234Jul 24, 2026Engine. Complaint Check Engine Light ON with DTC P012800 "The Coolant Temperature is Below the Specified Temperature" active and/or stored in the ME (N3/10). There are no drivability concerns related to this complaint. Cause Root cause varies Remedy Prior to performing any repairs for this complaint: With a cold engine, pressurize the high temp coolant circuit and while it's under pressure, release the cap on the low temp…
• 11035117Jul 17, 2026Engine, Electrical system. 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, August 6th, 2026. After August 6th, 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…
• 11035118Jul 14, 2026Back-over prevention (rear camera), Body and structure. Complaint Consistently reproducible erroneous parktronic warnings from front with every key cycle. Cause The parking sensors are detecting the front brush guard. Remedy Complaint must be consistently reproducible and can occur multiple times a key cycle without obvious cause. NOTE: The parking system serves solely as an aid. Please review both the system function and system limitations as shown in the Operator's…
• 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…
• 11033981Jun 17, 2026Electrical system, Back-over prevention (rear camera). Complaint Consistently reproducible erroneous parktronic warnings from front with every key cycle. Cause The parking sensors are detecting the front brush guard. Remedy Complaint must be consistently reproducible and can occur multiple times a key cycle without obvious cause. NOTE: The parking system serves solely as an aid. Please review both the system function and system limitations as shown in the Operator's…
• 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.
• 11033050May 22, 2026Transmission and drivetrain, Body and structure. 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, June 11, 2026. After June 11th, 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…
• 11032887May 19, 2026Transmission and drivetrain. Complaint Harsh upshifts, downshifts, or jolting in lower gears when accelerating. Cause Incorrectly installed (rotated) rotational speed sensors on the EHS (VGS Control Unit) can cause abnormalities in signals. As a result, poor adaptation values are stored and harsh gearshifts are felt. This only affects vehicles with VGS control units produced between days 185-296 of 2025 (July 4, 2025-October 23, 2025). Remedy…
• 11032736May 15, 2026Transmission and drivetrain, Suspension. 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, June 4, 2026. After June 4th, 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. Please include a copy of this NCU as…
• 11032586May 7, 2026Body and structure. Complaint Water ingress in the load compartment between the C and D pillars. Cause In the area of the rounding at the D-pillar, a leakage may occur between the rear side wall and the roof paneling. Remedy Troubleshooting: Locate the area of the leak by performing a pressure test and using leak detector spray or soapy water. To do this, tape up the rear vents on the D-pillars and set the ventilation system to the…
• 11031558Apr 24, 2026Other or unknown. Complaint The intent of this document is to provide workshops with helpful technical reference language. • Commonly used acronyms in LI's and TIPS cases. • Control unit names, numbers, and how to identify. • Network/wiring architecture groups to baumuster quick reference. • Platform to baumuster quick reference.
• 11031581Apr 21, 2026Engine. Complaint CEL ON with DTC P012800 "The Coolant Temperature is Below the Specified Temperature" active and stored in the ME (N3/10). There are no drivability concerns related to the complaint. Cause Root cause varies Remedy Prior to performing any repairs for this complaint: With a cold engine, pressurize the high temp coolant circuit and while it's under pressure, release the cap on the low temp coolant circuit and…
• 11031582Apr 20, 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.
• 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.
• 11031199Apr 8, 2026Electrical system. Complaint The outside mirrors do not fold in when locking with the radio remote control, even though the function is activated in the vehicle settings. Folding and unfolding still functions via pushbutton switch on the door. Cause The initialization data for the outside mirrors is lost in the door control unit. Remedy Replacing the control unit provides no remedy.
• 11030301Mar 25, 2026Other or unknown. Complaint The intent of this document is to provide workshops with helpful technical reference language. • Commonly used acronyms in LI's and TIPS cases. • Control unit names, numbers, and how to identify. • Network/wiring architecture groups to baumuster quick reference. • Platform to baumuster quick reference.
• 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.
• 11029093Feb 28, 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.
• 11029055Feb 28, 2026Engine, Electrical system. Mercedes-Benz AG (“MBAG”), the manufacturer of Mercedes-Benz, has determined that on certain MY 2019-2021 G-Class, S-Class and GT (463, 222 & 190 platforms) vehicles, the engine control unit software does not correspond to current production specifications. It is therefore possible that onboard diagnostics and/or exhaust gas emissions requirements may not be fulfilled. MBUSA will conduct a service campaign. An…
• 11029024Feb 24, 2026Body and structure. Complaint Water ingress at the sliding sunroof can lead to moisture in the interior. In some cases, the leakage may also be visible to the customer in the area of the overhead control panel. Cause The following causes can lead to water ingress in the area of the sliding sunroof and thus to moisture in the vehicle interior: 1. Incorrectly routed drain hoses: Water may accumulate in the rear area of the sliding…
• 11028988Feb 24, 2026Body and structure. Complaint After removing the transport protection from new vehicles, localized cloudy spots or streaks may appear on the paint surface. These marks are most commonly seen on the hood, fenders, and bumpers and are more noticeable on dark paint colors. Cause Moisture can become trapped under the full transport packaging. This moisture may penetrate the fresh paint, causing the paint layer to swell and result in…
• 11028834Feb 13, 2026Transmission and drivetrain, Electrical system. Complaint Check engine light on with the following fault is current in the VGS Control Unit: P084300 Oil pressure sensor 'A' has a short circuit to positive stored in VGS control unit. Cause Electrical failure of oil pressure sensor integrated into VGS Control Unit Remedy Intelligent Predictive Repair (IPR) recognizes this fault pattern and will provide the necessary repair suggestion. 1. Perform IPR and follow the…
• 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.
• 11028810Feb 11, 2026Engine. Complaint CEL on with Code P012800 "The Coolant Temperature is Below the Specified Temperature" Cause Under investigation. This is not an issue that affects drivability or performance and is not a safety concern. The vehicle remains safe to operate with this code, but the measures listed in the "Remedy" section are recommended. Remedy 1. Use VMI to check for Emission Extended Warranty – Engine Thermostat (incl.
• 11028270Feb 3, 2026Transmission and drivetrain. Complaint Only vehicles with a variable transfer case are affected. This can be identified through control unit N45 or N15/7 in the quick test. When accelerating with light load, vibrations or jolting sensation may come from the drivetrain. It may be mistaken for a harsh shift. Cause Modified oil quality of the transfer case over time Remedy 1. Check initial quick test for faults in the following control units.
• 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…
• 11027678Jan 15, 2026Engine. Complaint Customer states check engine light on in the dash. Vehicle has one or more DTC's Present P164B00, P164B09, P2B4400, P005A07, P005C07, P005A09, P005C09, P003C07, P2B5007, P003C09, P2B5009, P34C200, P34C109, P34C800, P34BE00, P34BD09 Cause Software and Hardware Remedy 1. Check for available Software updates for the Engine Control Unit ME N3/10. Perform update if available. 2. Check part numbers on ALL…
• 11027120Jan 6, 2026Engine. Complaint CEL on with Code P012800 "The Coolant Temperature is Below the Specified Temperature" Cause Under investigation. This is not an issue that affects drivability or performance and is not a safety concern. The vehicle remains safe to operate with this code, but the measures listed in the "Remedy" section are recommended. Remedy 1. Use VMI to check for Emission Extended Warranty – Engine Thermostat (incl.
• 11026961Jan 5, 2026Engine. Complaint Customer reports illuminated CEL. Additionally no start condition, lack of power, failure to recover from ECO stop, and/or poor acceleration. Cause • Under investigation Remedy Process FSCU and ME codes via guided test. Perform fuel pressure test on high and low pressure sides of system. Check and perform electrical testing from N118 X1 pin 1 to K40/5 S2 pin 1 Check from N118 X1 pin 2 to W10/1 with…
• 11026968Jan 2, 2026Electrical system. Complaint Noise interference when using the hands-free system (phone call). Cause The noise is caused by electromagnetic interference (EMC fault) affecting the microphone lines and thus impacting voice quality. The severity of these faults may vary depending on the vehicle.
• 11026833Dec 20, 2025Transmission and drivetrain. Complaint (Original LI document #: LI27.35-P-079039) Clicking noises from the electro-hydraulic control unit (EHS) when the vehicle is stationary and ECO Start/Stop is active (combustion engine is off). The noise is more noticeable outside the vehicle and in acoustically shielded areas such as closed rooms or garages. Cause The noise in the valve body (EHS) is caused by superimposed pressure peaks acting on the…
• 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.
• 11025471Nov 10, 2025Transmission and drivetrain. Complaint Possible complaints about shift quality, issues with learning the park lock, and slipping/rinse entries in the EEPROM or Transmission Health system following the replacement of the below components: - The electrohydraulic control unit (EHS valve body) in transmission 725.0/725.1 - The repair kit for the control unit (VGS) in transmission 725.0 Cause Missing, incorrectly installed, or damaged guide tubes…

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