I had a similar problem with my 95 850 T5R. It turned out that the battery wasn't charging correctly and ultimately failed. I also intermittently got the flashing yellow arrow and check engine light. Checking the codes it said wheel sensor.

So, first I went to my nearby Interstate battery shop. they tested the battery and told me it was gone. Got a new one and measured the voltage before and after starting. Didn't change. Oh boy. need a new alternator right? wrong. after I changed the highly corroded battery cable to the starter the voltage was a little higher, but not quite right. I did what any reasonable person would do. I ordered a new alternator. Well while waiting for the new alternator to arrive via FCP groton, I installed a new battery cable to the starter and then I noticed that the cable from the starter to the alternator was very loose. Tightened it and now I'm at about 14.2 volts after starting and no more non crank issues. How the heck did it get loose? oh well.

Also, I took each and every wheel speed sensor out, cleaned them and also sprayed cleaner inside the wheel connection point. No more intermittent yellow arrow.