Mercedes-Benz GLS 450 check engine light comes on

Filed May 22, 2026 · Engine · NJ

I am reporting a serious safety defect in my 2019 Mercedes-Benz GLS450. My vehicle experienced low oil pressure warnings and engine warning lights, which were diagnosed as a faulty oil pump solenoid valve. The repair required removing major engine components, resulting in a cost of $5,000 that I paid personally. It is important to note that Mercedes-Benz updated the valve design in the following model year, indicating that the company was aware of a defect in the original design. This demonstrates that the failure is recurring and not isolated, creating a serious safety risk—low oil pressure can lead to catastrophic engine failure while driving, endangering the driver and passengers. I request that the federal safety agency: Document this as a potential safety defect. Investigate the prevalence of this issue. Consider initiating a recall or safety notice for affected GLS450 vehicles.

Filed Feb 23, 2026 · Electrical, Engine · TN

The vehicle is experiencing deterioration of the main engine wiring harness insulation, resulting in exposed wires contacting each other. This condition has caused intermittent check engine lights and electrical fault codes. The dealership has confirmed that the wiring insulation has degraded, allowing wires to contact each other. The issue appears related to material durability of the harness rather than external damage. The concern is that continued deterioration could result in: •Sudden engine misfire •Loss of power while driving •Engine stalling •Potential electrical short circuit An unexpected loss of engine power at highway speeds could increase the risk of a crash. The dealership indicated that similar harness insulation concerns have been observed on other M256-equipped vehicles. This appears to be a potential safety-related defect involving engine wiring insulation durability.

Filed Mar 4, 2025 · Fuel system · CA

Vehicle check engine light came on early August 2024. Vehicle was brought in for service and checked for codes. B1F4500 Battery has excessive resistance B21059A The operating conditions of component have not been satisfied. Battery was replaced and rechecked. Po4427A Evap leak detected P04F000 Charcoal canister has a malfunction Smoke tested EVAP system to see if there was any leaks and tested the valves to make sure EVAP system was working correctly. Charcoal canister not actuating correctly so was replaced and checked. Gas cap also replaced Several days later Check engine light returns. Code continues to say "Small leak in the EVAP system." Every time the code is cleared it returns and Check Engine light returns. This has been going on for 7 months. Car cannot obtain the required SMOG inspection in California that is required for an annual registration of the vehicle. I believe the vehicle may need to be part of the Emission Service Campaign 2024030005 which has effected 16 other vehicles. Mercedes tells me that an update to the Engine Control Software will not be allowed because my vehicle is not one of the 16 vehicles that are currently effected by this issue. The issue is for the same make, model and year as my vehicle.

Filed Dec 6, 2024 · Engine · 91,000 miles · NC

The contact owns a 2019 Mercedes-Benz GLS450. The contact stated upon starting the vehicle, the check engine warning light illuminated intermittently. The contact stated that the failure had become consistent. The vehicle was taken to the dealer, where it was diagnosed that the engine oil pump valve and the camshaft adjuster had failed and needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure and referred the contact to the federal safety agency Hotline for assistance. The failure mileage was approximately 91,000.

Filed Nov 13, 2024 · Electrical · IN

Vehicle has just over 31k miles. ON multiple occasions, the vehicle randomly shuts off and displays a 48 volt battery error on the screen followed by a check engine light. This has happened in the middle of a busy intersection and at 75mph on the interstate. Each time it does this, I have taken it to a Mercedes dealer for repair/troubleshooting. THey perform the Mercedes required steps to repair the known issue and each time the issue persists. The car has been at a dealership for almost a combined 30 days now with no end in sight. I do not feel safe knowing that Mercedes cant seem to solve the problem and instead puts me back on the road knowing the car is not right and risks injury to my family as the issue has happened at low speed and high speed resulting in extremely dangerous situations for my family. I have 2 open PTSS cases with Mercedes USA (246121906 and 246113294). Researching this issue has revealed this is a known issue with their "mild hybrid" SUVS and many consumers have the same or similar experience to mine.

Filed Sep 26, 2024 · Engine · 38,000 miles · WA

The contact owns a 2019 Mercedes-Benz GLS450. The contact stated that while operating the vehicle, the check engine warning light remained illuminated, and the vehicle was jerking and hesitating while attempting to accelerate. The vehicle was taken to the local dealer who diagnosed and determined that the oil pump and check valve were faulty and needed to be replaced. The vehicle was not yet repaired. The manufacturer was notified of the failure. The failure mileage was 38,000.

Filed Sep 9, 2024 · Engine · FL

9/9/24 after 5pm I'm driving my car and the check engine light came one. I have a small autel handy scanner always in my car. I checked it right away and gives me the code P06DA (OIL PUM SOLENOID OPEN CIRCUIT - ELECTRICAL ISSUE). I stop on the side for a quick check, no knocking noise from the engine and runs good. I checked on the website (Mercedes forums) and a lot of people had the same problem (lemon???). Most of them talking that thanks God the solenoid stuck on full open (higher pressure oil) so there's no damage to the engine. Repair cost around $5000!!!!! That problem must be taken seriously from Mercedes! Thank you

Filed Jul 16, 2024 · Electrical · GA

Cluster Information Display Black out on and off. Cannot see speedometer and headup display also turns off. Problem occured 5/13/22, 6/17/22, and 6/13/23. Problem is still not fixed after going to mechanic 3 times. 7/16/24 went in to mechanic again for the same problem but mechanic concluded that there are no further solution possible to fix this problem. When the problem occurs, the cluster information display is blacked out for about 3 to 4 hours, and only fixed when 1 or 2 days are fixed. It is dangerous to drive without the cluster display which includes speedometer, remaining gas, engine warning light, and many more important information that is needed and required to drive safely without crash.

Filed Jan 9, 2023 · Driver assistance, Engine · IA

On four occasions my car has stalled while in traffic very early in my ownership and then it happened again today with my family in the car and nearly caused an accident. The entire dash lights up with every warning when it happens. Sometimes the check engine light comes on after I shut the car off and restart it. My Mercedes dealer has had it in multiple times for this reason. The last time it was in for this (May of 2022) they "reprogrammed" the entire car. It happening again today has really made me lose a lot of faith in the vehicle, especially since we purchased it for the safety factors. I read online that there are many others who have experienced this. Some say it is related to the 48V battery. I don't care what Make or Model or how expensive it is, a new car should NOT stall in traffic and should be looked into. Thank You.

Filed Sep 23, 2022 · Electrical, Engine · CA

This incident occurred around 5:50pm on Wednesday, September 21, 2022. I was driving on a merge connector between two freeways in San Francisco at about 60mph, when the vehicle threw a series of error codes and warnings on its displays, culminating with “shut down engine immediately”. The first error was a 48V battery system charging failure, and the second was a warning that coolant was too hot. The instrument panel and steering and brakes did not lose power, but the accelerator no longer worked, and the vehicle slowed down to about 35mph. I had to merge across 4-5 lanes of rush hour traffic at this speed (sketchy) to make it to the side of the freeway, and was able to exit safely and stop in a safe spot. Upon turning off the vehicle for a few minutes and then restarting it, a generic check engine light remained on afterwards. I had the vehicle towed to a Mercedes dealer where the fault(s) are currently being diagnosed. According to the dealer, they are in touch with MBUSA Engineering due to the nature of the fault codes. The vehicle had recently undergone a 50,000 mile routine service without any problems being flagged. The safety implications of this incident are clear: with no ability to match the speed of the flow of traffic, I could have been rear-ended or involved in a collision as I limped across the freeway to safety. I am fortunate that the vehicle had enough residual kinetic energy that I didn’t end up stuck blocking a freeway lane in rush hour traffic. Searching online for similar issues, this appears to be a known manufacturing issue with the mild hybrid inline-6 engine in this model of vehicle. For instance, all of the top Google hits for the term “GLS 48V battery failure” yield relevant and similar reports from other drivers, including summaries from consumer lawyers like this one: https://lemberglaw.com/mercedes-benz-gle-battery-electric-problems/