Modern automatic transmissions are very different from their predecessors. The amount of software that goes into a transmission control unit beggars belief, and we also have to remember that said control unit has to work in unison with others, including the all-important engine control unit.
Unfortunately, a little over 105,000 examples of the Mercedes-Benz GLE 450 and larger GLS 450 may have been produced with iffy transmission control unit software. According to the German automaker, the 9G-Tronic that equips affected vehicles may not fully downshift in certain driving conditions, therefore causing the inline-six engine to stall.
Merc's US division produced the suspect vehicles between February 1, 2018 and August 19, 2023 for the 2020 through 2023 model years. Of course, both the GLE 450 and GLS 450 hail from the Alabama-based Mercedes-Benz US International plant.
No fewer than six part numbers for the transmission control module software are listed in the report attached below, which further lists Mercedes-Benz AG as the supplier of the bugged software. As per the chronology filed with the National Highway Traffic Safety Administration, the German automaker started investigating reports alleging engine stalling while driving back in March 2022.
At that time, Merc failed to connect the reported incidents to the shifting abnormalities caused by the transmission control module software. Mercedes finally succeeded in duplicating the concern in May 2023, prompting further testing, investigations, and an analysis of potential failure mechanisms.
Photo: Mercedes-Benz
These efforts led to the development of new software, which can only be installed by authorized dealers via the OBD II port. Owners can look forward to Mercedes-branded envelopes arriving via first-class mail no later than April 16, informing them of the recall condition and urging them to schedule an appointment at the preferred dealer.
Stalling may occur exclusively in case of a downshift from seventh to sixth gear. Regarding the conditions that lead to engine stalling, the downshift has to be performed during a slight braking maneuver. Additional conditions also exist, including an aborted shift operation, simultaneous recuperation by the mild-hybrid system's starter-alternator, or low transmission oil temperature.
2020 to 2023 Mercedes-Benz GLE 450 and GLS 450 owners can determine whether their vehicles are included in this recall by entering the 17-character VIN on the automaker's site or the NHTSA's site. Between May 6, 2019 and February 6, 2024, the manufacturer received 261 field reports and 730 warranty claims regarding this problem.
Both the GLE and GLS were facelifted in 2023 for the 2024 model year, and these vehicles are not included in the aforementioned recall. The 450 series comes with 4MATIC all-wheel drive by default in the US market. At the moment of reporting, the GLE 450 and GLS 450 start at $69,500 and $87,000 (excluding the destination freight charge).
After a 1:43 scale model of a Ferrari 250 GTO sparked Mircea's interest for cars when he was a kid, an early internship at Top Gear sealed his career path. He's most interested in muscle cars and American trucks, but he takes a passing interest in quirky kei cars as well. Full profile
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