E46Fanatics

E46Fanatics (http://forum.e46fanatics.com/index.php)
-   E46 Xi Forum (http://forum.e46fanatics.com/forumdisplay.php?f=104)
-   -   transmission warning light (http://forum.e46fanatics.com/showthread.php?t=944605)

ned cox 09-14-2012 04:02 PM

transmission warning light
 
Any body dealt with transmission warning light? Car runs fine until I begin to slow down then it down shifts hard coming to a complete stop. There is no perceptable change coming up to speed. HELP

staticbelow 10-03-2012 09:52 PM

I have more or less the same issue. I just changed the thermostat because the service engine light came on and the dealer said that was why. (They also wanted $500 dollars to do it!) After installing the new thermostat on the way home the car started upshifting a little hard into 2 and 3, but the downshifts into 2 and 1 are really hard. I don't know if the new thermostat is related in any way but since it occurred after changing it I thought I'd mention it.

Anyone have any ideas? My car is a 2002 330xi with 99k.

SamDoe1 10-04-2012 09:17 AM

Change the fluid and filter. Change, do NOT flush. Very important.

staticbelow 10-05-2012 02:21 PM

SamDoe1,

Did that work for you? There seems to be a lot of back and forth about whether or not that is a good idea. I've read posts for about 2 hours now and it seems to be an even split between changing the fluid and filter, flushing the system, and people that say you shouldn't touch it at all. Could you supply a little background for your recommendation?

redbull 325is 10-06-2012 10:24 AM

Quote:

Originally Posted by ned cox (Post 14732282)
Any body dealt with transmission warning light? Car runs fine until I begin to slow down then it down shifts hard coming to a complete stop. There is no perceptable change coming up to speed. HELP

Trans warning light is probably due to torque convertor lockup or maybe a bad maf (where it gets a load sensing from).

The harsh downshifts are fixed by a firmware update, we've done hundreds at work.

White_Knuckles 10-06-2012 03:04 PM

I'm in on the MAF. I changed out my Intake cam sensor and was instantly greeted with the Trans lamp on start-up! Um, I forgot to hook-up the MAF connector. Scared me good but never could figure what the @#$ MAF data has to do with transmissions? I thought the evil programmers at Siemens just liked to scare us.

RB's post helps understand why MAF "load" data is involved.

staticbelow 10-17-2012 08:13 PM

It turns out my problems were related to the MAF sensor too. When I plugged it back in it must not have clicked in all the way and came apart. Once I plugged it back in the hard downshifts disappeared. Thanks to everyone for the help. This forum continues to save me money :)


All times are GMT -5. The time now is 07:11 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
(c) 1999 - 2011 performanceIX Inc - privacy policy - terms of use