One of the best upgrades for any offroad vehicle is oversized offroad tires. They offer more traction and more ground clearance. The only issue is that until now, the Sprinter only allowed you to install a max tire size of 33" (275/70/17). Now, thanks to the tire ROM from FreedomVanGo and Renntech, you can install up to a 35" tire without issue.
Why is the tuner needed? The Mercedes onboard computer (ECU) checks both the wheel speed and the GPS speed the van is traveling.
By installing a tire larger than a 275, your wheels will turn slower for a given speed (lower wheel RPM) which will therefore cause the computer to think there is a problem. The ECU will then disable Adaptive Cruise Control and Emergency Brake Assist.
The good news is that Renntech and FreedomVanGo finally have a fix. By plugging in the Renntech Tire ROM to the OBD2 port on your van it will change the acceptable tire size inside the van's ECU allowing all systems to function as intended. You can then remove the ROM and you're done.
VIN MUST BE SUPPLIED BEFORE WE ARE ABLE TO START THE TUNING PROCESS. MODULES HAVE TO BE TUNED AT FREEDOMVANGO AND ARE NORMALLY SHIPPED WITHIN 24 HOURS OF RECEIVING YOUR VIN NUMBER. IN ADDITION WE NEED THE TIRE SIZE AND BRAND YOU ARE INSTALLING AND THE HEIGHT OF THE VAN WITH NEW TIRES, AND LIFT FROM THE GROUND TO THE BOTTOM OF THE DISTSRONIC SENSOR IN THE FRONT.
* No returns on Renntech Tuners. Due to the nature of installing a tune, any return or refunds would be at the sole discretion of Renntech. Returns on tunes are only accepted in situations where there is a problem that is unable to be resolved.
*Note - If your van is equipped with remote start equipment, you may need to unplug that remote start equipment to properly load the tune. We recommend installing at home and not before a big trip so that if there are any issues with the installation you are not at a remote location.