2020 Mercedes-Benz GLS 450 Fuel system Problems
- Complaints
- 7about this part
- Share
- 19%of 36 total for the year
- Median mileage
- 2,600miles
- Trend
- Not enough dataFewer than 15 complaints, too few for a reliable trend.
NHTSA recorded 7 complaints about the fuel system of the 2020 Mercedes-Benz GLS 450, 19% of the 36 complaints for this model year. Where a mileage was given, the median is 2,600 miles. 1 a fire, according to the filers. 1 recall campaign on record is filed under a similar system.
Fewer than 15 complaints name this part, so treat the figures as a rough indication only.
Example complaints
Selected from NHTSA records; personal details are removed. They are consumer reports, not findings.
“We purchased a new 2020 mercedes benz gls 450 in october 2019 from the oakland dealership and shipped the car to hawaii. The vehicle is now 117 months old and has about 4100 miles. Because our vehicle is lightly used we arranged for mercedes benz to supply and installed a 'battery minder' to keep the vehicles 48 volt system charged when we are away for an extended time. However we did not have the battery minder hooked up at this time because we are using the vehicle on a weekly basis. …”
NHTSA complaint #11402929, filed 2021-03, 4,200 miles“On numerous occasions, when either slowing down or in a slow turn, the engine dies and will not reengage until I have turned off the vehicle, exited, then reentered an started the vehicle. I have had passengers in the vehicle who will attest to this occurring, in fact, the last time it happened, I was almost broadsided when the vehicle stopped in the middle of a left-hand turn, crossing three lanes of oncoming traffic. The vehicle has been to the dealership at least three times and it's either a software update requirement or we can't duplicate the issue. …”
NHTSA complaint #11465253, filed 2022-05“While driving, vehicle has abruptly stopped/engine turned off causing car to not accelerate and come to a stop. One instance was on a busy freeway, causing our family to pull off the interstate with nearly no curb, risking rear-end collision due to the abrupt stalling of the vehicle. In this instance, the 48 volt battery failure warning, engine overheat warning, engine light warning came on. When MCB dealership evaluated the vehicle, there were no stored associated error codes and MCB service returned the vehicle to me saying that the issue did not occur when they drove it. …”
NHTSA complaint #11464919, filed 2022-05“We were driving the vehicle at about 30 MPH on a road when suddenly the engine completely shut off. There was no more power steering and no warning that it turned off. We got the car slowed down and once we came to a stop the car put itself in Park. After that we could restart it and keep driving with the car acting very different. This then happened again later on in the day going about 20 MPH up to a stop light. It shut itself off and luckily we were able to come to a stop with the brakes without running into the intersection and no one hitting us from behind. …”
NHTSA complaint #11427911, filed 2021-08“The engine wiring harness insulation near the ignition coil connectors prematurely deteriorated due to prolonged exposure to engine heat in the turbocharger/exhaust area. Multiple wiring connectors exhibited brittle, cracked insulation with exposed conductors. The degraded wiring began shorting within the ignition system, causing engine misfires, ignition circuit faults, and eventual loss of engine operation. …”
NHTSA complaint #11736819, filed 2026-05Related recalls
- 21V961000Dec 13, 2021Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2019 AMG G63, C300, E300, G550, AMG GT63, AMG GT53, 2019-2020 A220, GLA250, GLC300, 2016 C300, 2020 AMG…Covers: Mercedes-Benz GLS 450 2020, C300 2016, 2019, A 220 2019–2020 +18 more
Related service bulletins
- 11036999Aug 15, 2026Dear 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…
- 11035490Jul 31, 2026This NCU replaces the prior NCU issued on May 15, 2025, and contains additional MY 2023 and MY 2024 vehicles which are highlighted below.
- 11019016May 30, 2025In 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…
- 11018625May 15, 2025In our continuing efforts to ensure the proper performance of Mercedes-Benz products and to enhance the satisfaction of our customers, Mercedes-Benz USA, LLC (“MBUSA”) is…
- 11017203Apr 22, 2025Complaint A pulsating knocking noise (e.g. clattering) can be heard underneath the bench seat, particularly in the case of a full tank (1/1 fill level). Cause The vibrating air…
- 11014402Feb 21, 2025Complaint 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…
- 11013179Jan 24, 2025Complaint 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…
Fuel system: other model years
Other parts of the 2020 Mercedes-Benz GLS 450
18 complaintsEngine
9 complaintsForward collision avoidance
7 complaintsOther or unknown
4 complaintsTransmission and drivetrain
4 complaintsAir bags
2 complaintsBack-over prevention (rear camera)
2 complaintsBrakes
2 complaintsBody and structure
2 complaintsVisibility (wipers, defrost, mirrors)
2 complaintsSeats
1 complaintsSteering
1 complaints
← All problems reported for the 2020 Mercedes-Benz GLS 450
About this data. Data from NHTSA (ODI) complaints, recalls, TSBs and investigations, updated Oct 31, 2026. Complaints are unverified consumer reports and may be duplicated or inaccurate.
To check a specific vehicle for open recalls, use its VIN at nhtsa.gov/recalls. Methodology