Embarking on a DIY project to correct the mileage on your Mercedes-Benz can seem daunting, but with the right approach and tools, it’s achievable. This guide details a personal journey of successfully adjusting the mileage using a chip modification, offering insights and lessons learned along the way. The process focuses on utilizing readily available tools and online resources to perform Xentry Mileage Correction for your Mercedes-Benz cluster.
The initial hurdle was sourcing a compatible instrument cluster. After extensive, and often fruitless, searches on eBay for a specific unit (210 540 3448) that conveniently displayed mileage, the decision was made to directly alter the existing chip. A donor speedometer was acquired, though unfortunately arriving damaged due to inadequate packaging. However, the crucial component, the 93LC66 microchip, remained intact and was the primary focus.
Programming the chip required a suitable device. An initial budget programmer (£16) proved ineffective, failing to operate on Windows 7 as advertised. This was returned and replaced with a more robust programmer (£50) compatible with Windows 10. After downloading the latest software from the manufacturer’s website, the new programmer, specifically the TL866II Mini Pro USB Universal Programmer, was successfully set up and ready for use.
Removing the chip from the Mercedes cluster is a delicate process. Lacking a heat gun, a soldering iron was carefully employed, following techniques demonstrated in online tutorials. A critical lesson learned through an earlier mishap: Mercedes cluster chips are glued in place. Insufficient heat can lead to tearing the chip along with underlying circuit tracks, irreparably damaging the cluster. This unfortunate experience necessitated acquiring a second donor cluster from eBay.
This second attempt proved successful. The chip was extracted and its data read. Seeking expert guidance, a request for assistance was posted on the DK forum. A knowledgeable individual provided invaluable support, furnishing the hexadecimal code corresponding to the desired mileage and specifying its programming location within the chip. Crucially, it was revealed that the mileage data in these chips is stored in kilometers within the first two lines of code, subsequently translated by the cluster to miles or kilometers as configured.
However, post-programming, a new issue arose. The cluster, now displaying the intended mileage, indicated a hydraulic fluid level fault. Further online research revealed that the donor cluster, despite sharing the same part number, originated from a wagon variant of the Mercedes-Benz. This explained the spurious warning light. Pin 1 on the cluster’s left socket is designated for the hydraulic fluid sensor, absent in wagon models. To resolve this, the cluster was reopened, and a jumper wire was soldered from pin 1 to pin 3 on the right socket (ground). This effectively bypassed the hydraulic fluid sensor input, eliminating the erroneous warning.
With this final adjustment, the xentry mileage correction was successfully completed. This DIY endeavor, while involving some setbacks and requiring resourcefulness, marked the final step (hopefully!) in a larger vehicle conversion project.
