Experiencing issues with the Anti-Slip Regulation (ASR) system in a 1992 Mercedes 500sl can be incredibly frustrating. Recently, I encountered a perplexing problem with my 1992 Mercedes 500SL where the ASR system light illuminated, triggering a disconcerting “limp home mode.” This situation occurred while driving on the highway, immediately reducing engine power and significantly limiting the car’s performance. Managing to exit the highway at a reduced speed, I then faced a red battery light, culminating in the engine completely stalling.
Upon restarting the vehicle, the ASR light was initially off, and the 1992 Mercedes 500SL seemed to drive normally. However, this respite was short-lived. Seeking professional help, I took my car to a local Mercedes repair shop, not an official dealership, hoping for a swift resolution. The initial diagnosis led to the replacement of two motors supposedly related to the ASR system. This repair, involving part # 0005453165, cost a substantial $1,500 for parts and labor. For a brief period of two months, the car operated smoothly, leading me to believe the problem was resolved. Unfortunately, the ASR issue resurfaced, dashing those hopes.
The repair shop then proceeded to replace the ASR sending unit, part # 0005401417, incurring an additional expense of $720 for parts and labor. Despite this further investment, the ASR problem persisted, occurring sporadically in the days following the sending unit replacement. At this point, the shop’s diagnosis shifted towards the main computer, suggesting it was the root cause. Consequently, they installed a new electrical accelerating unit, part # 1295450132, at a significant cost of $2,160 for parts and labor. Driven by the hope that this computer replacement would finally resolve the persistent issue, I reluctantly agreed to the considerable expense.
However, my optimism was quickly shattered. Barely a mile from the repair shop after picking up the car, the dreaded ASR problem returned. The console light illuminated once more, and the 1992 Mercedes 500SL entered the familiar ASR “limp home mode.” Disappointed and frustrated, I immediately contacted the shop and returned the car, requesting the removal of the newly installed computer since it had clearly not fixed the problem. To their credit, the original electrical accelerating unit was reinstalled, and I received a credit for the cost of the new computer module. The over voltage protection relay was also tested with a new unit, but, predictably, the ASR issue remained unresolved.
In a perplexing turn of events, without any further repairs or diagnostic testing, the owner of the repair shop claimed to have driven the 1992 Mercedes 500SL throughout a week without the ASR system triggering even once. Trusting this assurance, I picked up the car again. However, barely a mile from the repair shop, on Friday, March 4, 2003, the ASR console light illuminated yet again. The car promptly began the ASR “limp home mode” sequence: reducing engine output power, and, as the car speed decreased below approximately 20-25 mph, the battery light illuminated, and the engine stalled completely. This frustrating cycle repeated five times before I could finally limp the 1992 Mercedes 500SL back home. Each time, I had to turn the car off, restart it to temporarily reset the system, only for the ASR light to reappear minutes later, initiating the same disruptive process.
My experience has led me to seriously doubt the repair shop’s competence and honesty. It seems highly improbable that they genuinely drove the car for a week without encountering the ASR issue, given its immediate recurrence upon my pickup. Furthermore, their claim that the ASR module was only installed in the SL for two years (1991-92) and subsequently discontinued, along with their assertion that Mercedes possesses limited technical information for repairing the ASR system in this model year, appears to be demonstrably false. The ASR system is a known feature in Mercedes-Benz 500SL models beyond 1992, and comprehensive technical resources should be available for such a system.
It is increasingly apparent that the repair shop either lacks the technical expertise to accurately diagnose and resolve the ASR problem in my 1992 Mercedes 500SL, or they are aware of the actual cause but are attempting to avoid honoring any repair warranty by correctly replacing the necessary components. Their approach seems to have been to indiscriminately replace parts, hoping that one of these arbitrary changes would coincidentally address the underlying issue. To date, I have spent over $2,220 on parts and labor, yet the ASR problem remains exactly as it was when I initially brought the car in for repair.
Considering the lack of progress and the mounting expenses, I am now contemplating taking my 1992 Mercedes 500SL to an authorized Mercedes-Benz dealer for repair. However, I firmly believe that the current repair shop should either successfully fix the problem they were entrusted to resolve or provide a full refund for the ineffective work they have performed to date. I am scheduled to return the car to them on Monday, seeking a more satisfactory resolution.
Seeking further insights, I posted my experience on an online SL forum. Several replies suggested that the problem might stem from a faulty wiring harness, potentially another costly component to replace. This raises further questions: Have others encountered similar ASR system problems with their 1992 Mercedes 500SL? And crucially, what is the connection between the ASR system malfunction and the battery light illumination and subsequent stalling? Could this be indicative of a battery or alternator voltage issue exacerbating the ASR problem? Any information or guidance on these matters would be greatly appreciated as I navigate this frustrating repair journey with my 1992 Mercedes 500SL.
