Sirhc1995

I have an 04 525i Sport, bought it back in July at 210k miles, it has 2 previous owners. I have all service records which show about $8k in repairs so the car has alot of new parts. A few weeks ago I took the car out at night and when I pulled away from my house the car hesitated for a second then the RPMs jumped to 6k and the car switched itself to automatic mode (I drive in DS Manual alot) then I got the transmission fault message. I drove to the nearest gas station and turned the car off then on, no error messages afterwards, pulled out from the gas station and right when I was turning onto the highway it did it again. I pulled on the side of the ramp and, turned it off then on again then drove around the highway back to my house.


It did this for about 3 days, then I took it to the mechanic shopped that serviced this car, he said it could be the battery (this car had battery issues when I bought it and it had to be replaced) he didn't have time to diagnose it since he was busy so I took it to AutoZone and my battery was at 45% 12.1v while the car was on and idling. Autozone said that my battery needs a charge, I got codes ran at AutoZone as well (I know that's not the best place to get codes on a bmw) but it showed 2 codes, one I forgot but was for a generic trans error fault code and the other was 4f8a which said ratio monitoring with gear 2-3. I went home and double checked my battery connection's, the positive was on good but moving the cable jiggles the connection, I left it alone and I haven't gotten the trans fault since.


Now I drive slow and careful from gear 2 and quickly shift to 3rd but even when I shift too early or the shift gets denied and keeps me in 2nd it will still drive fine in 2nd gear until I attempt the shift again. Researching gives me suggestions with the Mechatronics Sleeve and/or solenoids and the first place to check is the battery. My battery is low but haven't had the time to have it charged up and it hasn't happened since so I just kind of kept putting the issue off until I got the money for a new tranny (even though I probably don't need a new one), funny thing is the mechanic said the tranny was replaced around 110k miles with a brand new one. Until I can get him to look at it I'm only stuck on the battery being the issue and continuing to drive carefully in 2nd gear while quickly shifting to third. My other gears are perfectly fine. No noise coming from the tranny, car drives smooth and idles quiet and shifts fine to me.


I'm just confused as to why this issue seemed to magically go away, was it really just the battery or some electronics in the car acting up for a second? I heard e60s have buggy electronics. I got a ABS light a split second a day before the transmission fault error came. This all seemed to happened after I got 4 new tires. So many possibilities and I'm just confused what it could be until I get it to the mechanic

Edit: I also had Engine light come on once a month or so ago and stayed on for about a week then went away on its own, BMW said it's because of my muffler delete. It came on again when the engine revved to 6k when my trans fault issue came and went away an hour later. Not sure if that indicates anything

seanjordan20

It's a very common issue. You want it to go away with a restart. Change the gaskets and solenoids with fresh fluid and filter and you'll be fine

Sirhc1995

Will do, hopefully I can get it to the mechanic soon, I don't have a lift or leveled driveway to do it myself. He did all the work on this car anyway so it he knows every piece of it