Mercedes GLS Problems: 4 Issues To Look Out For

The Mercedes GLS is the top-tier GL-class vehicle; it is the S-class of the SUV world, and it is one of the very few cars competing in the full-size luxury crossover market, but it does have some common problems.

The Mercedes GLS suffers from electronic gremlins, 48V secondary battery malfunction, inferior interior plastic, and an ineffective HVAC system.

To help you make a more informed decision, we’ve broken down all of these common issues and looked at some Mercedes GLS recalls you need to be aware of (especially if you have one of these models).

2022 brilliant blue metallic mercedes benz gls 450 4matic towing a airstream trailer

4 Common Mercedes GLS Problems

1. Electronic Gremlins

The Mercedes GLS is the creme de la creme of SUVs from the Mercedes stable, and with that comes a plethora of gadgets and features.

The one negative is the chances of some of it going wrong, and numerous owners complained of features like the auto-wipers, no-touch trunk release, some driver assists, parking sensors, and dashboard screens periodically not working for no reason.

Until now, there have been numerous updates to the software of the GLS to counter these problems, but there are still people that have these problems.

2. 48V Secondary Battery Malfunction

The Mercedes GLS, like the other GL models like the GLE and GLA, uses a 48V secondary battery to help with the start/stop function and other high amperage features.

The battery does not get charged by the car’s system or very little and will later fail, resulting in some owners’ cars just randomly dying when the start/stop function kicks in.

This happened with some who owned the GLS as early as 5,000 miles (8,047 kilometers) which is quite alarming.

3. Inferior Interior Plastic

For a vehicle with a starting MSRP of $77,850, the GLS450 many owners found the interior plastic quality, not to their liking.

Some panels close to moving parts, like the folding rear seats, tend to get damaged easily, and some plastics on the dashboard are tough and feel cheap to the touch.

4. Ineffective HVAC System

Almost all owners of the Mercedes GLS complained that the HVAC (Heating, Ventilation, and Air Conditioning) was less effective than other vehicles.

The system takes a long time to heat up or cool down the vehicle, and the rear vents that give airflow to the rear have an abysmal performance where the passengers can’t feel any difference in air temperature.

Mercedes GLS Recalls

While recalls fix vehicle issues, there is still a chance that some cars never got fixed.

Either the owner did everything DIY or took it to a private mechanic who never knew about the recalls.

So it is advantageous for you as a potential buyer or owner of a Mercedes GLS to learn about these recalls. 

And if you already own a GLS, take your vehicle to a dedicated Mercedes-Benz dealer or trustworthy mechanic as soon as possible to rectify these problems.

2017 Recalls

  • 2017 GLS63 AMG vehicles may have an inaccurately calibrated OCS (Occupant Classification System)on the front passenger seat that can incorrectly classify the passenger as a child seat and deactivate the passenger airbag.
  • 2017 GLS63 AMG vehicles may have an electric power steering connector that is not correctly sealed, allowing moisture to enter the control unit and resulting in loss of power steering.
  • 2017 GLS450 4Matic vehicles may have too much bulkhead insolation that could cause the front windscreen not to completely bond correctly to the vehicle’s chassis in the production phase resulting in poor protection from the frontal airbags during a crash.
  • 2017 GLS63 AMG vehicles, in certain types of crashing scenarios, the center console can detach and fly around the cabin resulting in occupant injury.

2018 Recalls

  • 2017 GLS450 and GLS63 AMG vehicles may have a passenger rear door lock on the driver side that indicates it is locked but isn’t, thus not complying with the FMVSS (Federal Motor Vehicle Safety Standards).
  • 2017 to 2018 GLS550 4Matic vehicles may have a passenger rear door lock on the driver side that indicates it is locked but isn’t, thus not complying with the FMVSS (Federal Motor Vehicle Safety Standards).
  • 2017 GLS550 4Matic and GLS63 AMG vehicles equipped with ACS (Active Curve System) in certain driving conditions, the oil in the ACS reserve goes below the minimum level and starts foaming up and leaking out of the vent holes resulting in an increased risk of fire.
  • 2018 GLS450 and GLS550 vehicles, the rear brake caliper pistons were not correctly coated during manufacturing which can cause gas to be released into the brake system resulting in reduced braking performance.

2019 Recalls

  • 2017 model-year vehicles may have a software problem causing the eCall (Emergency Call Function) to send out the wrong time and date and even incorrect GPS coordinates.

2020 Recalls

  • 2020 GLS450 and GLS580 vehicles may have a rear door window trim that can detach, causing a road hazard.
  • 2020 GLS450 vehicles may have incorrectly placed air conditioning drain hoses that can cause water to drain in the passenger compartment.
  • 2020 GLS450 vehicles may have insufficient welds on the rear cross member that can cause it to crack while towing and cause it to detach while driving.
  • In 2020 GLS450 and GLS580 vehicles, the front and rear shock absorbers seals may leak and fail prematurely, resulting in decreased handling and control.
  • 2020 GLS450 and GLS580 vehicles equipped with the illuminated Mercedes-Benz start in the grill may have poor electrical ground. The poor ground can affect other components sharing the exact grounding location, like the power steering, wipers, and left headlight.
  • 2020 GLS450 and GLS580 vehicles may have a fault in the instrument cluster software can cause the deactivation of the illumination on certain interior switches, including the hazard switch, which fails to comply with the FMVSS standards.

2021 Recalls

  • 2017 to 2021 model-year vehicles may have a software problem causing the eCall (Emergency Call Function) to send out the wrong time and date and even incorrect GPS coordinates.
  • 2017 GLS450 vehicles, the communication module may have been disabled during the recall of the eCall.
  • 2021 GLS600 and GLS63 AMG vehicles may have a fault in the instrument cluster software can cause the deactivation of the illumination on certain interior switches, including the hazard switch, which fails to comply with the FMVSS standards.
  • 2020 GLS450 and GLS580 vehicles, during certain driving, the ESP (Electronic Stability Program) may apply torque only to one of the front wheels, causing the car to pull to one side and not comply with the standards of the FMVSS.
  • 2020 GLS450 vehicles, the surface of the dashboard isn’t securely held onto the base material, causing it to impair the inflation of the frontal airbags.
  • 2021 GLS450 and GLS580 vehicles may have incorrectly placed air conditioning drain hoses that can cause water to drain in the passenger compartment.
  • 2019 to 2021 model-year vehicles, the MBUX (Mercedes-Benz User Experience) can turn the display black and remain black even after reboot and startup, resulting in the rearview camera not displaying, thus failing to comply with the FMVSS standards.
  • 2020 GLS580 vehicles, the software in the airbag control unit may be programmed incorrectly, resulting in the driver’s airbag being deployed improperly during a crash.
  • 2020 GLS450 and GLS580 vehicles, the seats may have been assembled incorrectly, resulting in them being unable to restrain the occupants properly during a crash.
  • 2020 GLS450 and GLS580 equipped with gasoline engines; during the process of manufacturing the fuel system, particles trapped between the fuel rail and injectors caused it to leak fuel, increasing the fire risk.
  • 2021 GLS450, GLS580, and GLS63 S AMG vehicles, the rear window of the tailgate can detach due to insufficient bonding and can cause a road hazard.

2022 Recalls

  • 2017 to 2022 model-year vehicles, an error in the communication modules SIM card software can cause the system not to connect to mobile networks, thus disabling the eCall system.
  • 2020 to 2022 GLS450, GLS580, GLS600, and GLS63 AMG vehicles, the ground cable to the 48V battery under the passenger front seat isn’t properly fastened, resulting in the cable overheating and can cause a fire.
  • 2018 to 2021 model-year vehicles, the rearview camera may not display an image due to a software error and thus not comply with the FMVSS standards.
  • 2020 GLS450 and GLS580 vehicles, the front airbag wiring is routed incorrectly, resulting in the airbag not deploying correctly during a crash.
  • 2020 to 2021 GLS580, GLS600, and GLS63 AMG vehicles, the rear window trim bars can detach due to a manufacturing error, causing a road hazard.
  • 2020 to 2022 GLS450, GLS580, and GLS63 AMG vehicles, the locks in the third-row seatbacks may fail during a crash due to a manufacturing error.

Source: Kelly Blue Book

2014 designo diamond white bright mercedes amg gls 63 4matic driving through the country side

Final Thoughts On Mercedes GLK Problems

The Mercedes GLS has very few faults compared to its siblings, the GLA and the GLE, with only the HVAC and the 48V battery system being the most significant problems.

The best thing to do if you own a Mercedes GLS is to take it to a Mercedes dealership and have them check for any recalls that haven’t been completed.

If you are in the market for a used Mercedes GLS, get a full vehicle history report and avoid any models with an outstanding recall.

Hopefully, you found this article helpful, and you can go to your next Mercedes GLS test drive knowing what to look out for.

FAQs

Is The Mercedes GLS Reliable?

Compared to its competitors, the Mercedes GLS scores the second lowest in quality and reliability in the large premium SUV segment in J.D. Power. To keep in perspective, the Land Rover Range Rover scored higher in reliability and quality than the GLS, which says a lot.

Is Mercedes Gls 450 Expensive To Maintain?

Yes, compared to even its German counterpart, the X7, it costs 50% more to maintain the GLS 450 over the X7 xDrive50i. The Mercedes GLS, on average, costs up to $1,573 per year in maintenance, while the X7 is only $989, and the cheapest to maintain in the large premium SUV segment is the Lexus LX, with only $507 yearly maintenance cost.

Is Lexus More Reliable than Mercedes?

Yes, Lexus overall is one of the most reliable car manufactures in the world and is usually in the top 3 positions for reliability every year. At the same time, Mercedes has dropped in the rankings to 23rd overall out of 28 manufacturers.