I have just acquired an 02 Sprinter 2500. It looks like it should have 195/70 15 on the front and 225/70 15 on the rear. It has 225's all the way around. Also the traction light and ABS lights are on. My thoughts are that if the wheels aren't turning at the design speeds that will throw off the computer and cause the "traction", problem.
I need all the help that I can get. Thanks in advance.

 

My '02 FL Sprinter 2500 140WB came with LT225/70R15 112D all around, and need all four tires to be the same size to not trigger the ABS traction control. Different sized tires will spin at different speeds and ABS prevents different tire speeds or loss of control.
What makes you think yours needs different sized tires? 195 front / 225R?
The tire label tells you the right one.
I replaced all 4 tires with Pirelli Scorpion LT 235/75R15 110D since I do not fill with weight and like the reduced RPMs and improved mileage on highway, and no traction light problems.