I have searched everywhere and cant find the answer. I have a 05 545 with 145k miles. My tranny started to run odd due to low fluid. It would go into Trans. Failsafe every once in a while but it would clear with a restart. Well it did it again but it will not clear any more. I have added fluid to the correct level. Replaced the battery and changed the crankshaft sensor but it will no clear yet. Even if you just turn the key to the first position it will run through the regular process and then the trans Failsafe will come on so I'm hoping its something simple/stupid. Car settling for two weeks now. Its hard to bring it somewhere because everything is about a half hour away from where I live.

 

buy a cable and software and pull the codes?
there must be a sensor or solenoid with an open circuit possibly.

 

I finally found my scan tool and got P17E8. I erased the code and my Trans failsafe went away. Im just hoping it was because it was low on fluid (it took three quarts) and not something major. Yeah I know, fix the leak. What do y'all think?

 

a trans uses the fluid for its hydraulics. if you were low on fluid, you probably had air get in the system and a weak application of clutches. which in turn would cause slippage and throw the trans into fail safe.