In recent months, rumors have circulated around various towing sites that all-wheel drive Subaru vehicles can be towed with only two wheels on the ground if you remove a certain fuse from the fuse box. This information is posted without references to any original sources and is therefore unfounded. Transporting any all-wheel drive Subaru built after 1990 on two wheels can result in serious damage to the drive system of the vehicle. Older versions of Subaru vehicles such as the GL were a form of 4WD or an early version of all-wheel drive and could in some instances be towed on two wheels if the 4WD control was in the 2WD position and the transfer case lever was in the FWD position. Subaru vehicles have progressed through several AWD systems and the company states that none of their vehicles should be transported with just two wheels on the pavement.
While the source of this misinformation may not be known, it might be traced back to the method used on many Subaru vehicles for dealing with a flat front tire. Most late model Subaru vehicles if they suffer from a front flat tire require that a full-size rear tire be transferred to the front and that the compact spare be placed on the rear. The instructions in the owner manual then state that a spare fuse should be placed in the “FWD” slot in the fuse box. This disables the AWD system as far as driving on four wheels is concerned. It does not disable the system as far as towing on two wheels is concerned. Subaru states that if the vehicle is transported, it must be done with all four wheels off the ground.
So if the AWD is disabled when a fuse is installed in the “FWD” fuse slot when a “temporary use, compact spare” is installed, why does it not also work for towing? Disabling the AWD only allows for a dissimilar sized tire to be used on the vehicle and in fact, Subaru states it can be done for only one tire. If two compact spares are installed on the vehicle, even with the AWD system disengaged, the drive system will be damaged. Subaru’s AWD system requires that all four wheels be turning and that disabling the AWD will allow one wheel to turn at a different speed than the remaining three wheels. If two compact spares were installed, the system could not compensate for the tire size differences. Since the system is not fully disengaged, use of two compact spares will damage it just as towing on only two wheels would damage the system. The AWD system requires at least four wheels to be turning at close to the same speed at all times and the fuse procedure works on only one wheel at a time. Lifting one end of the vehicle prevents two wheels from turning and requires the other two wheels to turn. This can damage the car.
In dealing with all-wheel drive cars, we must remember that with most modern AWD systems, we are dealing with more than the drive system. Cars are increasingly coming with traction control and stability control systems. These systems work to counteract slippage of one or more wheels, in some cases even with the engine off. Stability control systems are most often designed to apply brakes to counteract slippage of wheels. If the computer notices that two wheels are not turning, it will try to counteract the problem by reducing the speed of the wheels that are turning. There are other control systems on various cars that can cause towing problems and it is more important than ever that every tow operator understand the tow procedure established by a vehicle manufacturer and follow that procedure at all times.
For this information, I reviewed owner manuals for every model of Subaru for every year for the last 20 years and they are my source for the information given in this article.