1992 325i Auto Transmission Light ON

Hi guys, been reading around around this issue with the transmission computer light ON and the car being in "home limp mode" on a 92 325i and need anyone's input here. I am trying to help my wife's son here since he is the owner of this car. My problem basically resides on being unable to read the codes out of the Tranny computer due to a lack of an equipment to get the codes. But I was able to check each individial sensor / solenoid from the transmission from the computer connector and so far I got readings from each of them. From previous experience I would expect an open winding for a bad sensor or solenoid. Also I have checked the computer fuse, disconnected and connected the battery and did the manual codes retrieval procedure for the ECM for OBDI cars and nothing comes up. At any point I have not been able to have this light get OFF, it is a hard fault no matter what I do.

At this point I think I got I may have two possible issues here, a bad computer or a bad tranny? But before ruling anyone out, which piece of equipment you recommend to be able to read the codes from the TCM that does not cost an eye? I have seen somes at Ebay but want to make sure they work before attempting to get them.

Appreciate your help here, we are not in posistion to take this car to a BMW dealer at this point.

On my phone so I'll make this short:

1. Search the forum for"stomp test"

2. On these cars it is called a TCU (tranny control unit).

3. Good luck. 9 for 10 the auto tragic tranny is done for.

Ed.

SELL IT.

If you cant maintain it, it will only become a burden.

Guys, thanks for the replies, but in order to sell it, I need to have this fixed up first. From what I have read, the stomp test will not read any codes stored in the TCU, it will read those from the ECM, right? That's the reason I asked about what piece of test equipment I should get to be able to get those codes out of the TCU. This car is OBDI, so it got the big round 20 pins plug in the engine compartment.

Thanks, luiso16

I dont see how having the transmission "fixed first" is going to help you.

Sell the car.

IF, you cant take it to the dealer, and cant assess the condition of the vehicle
without "test equipment" then it sounds like it is out of your scope of practice.

Try some good ol' fashioned maintenance first..
Check, inspect, and replace as necessary.
Check the fluid, Flush fluid, change filter, refill with good fluid.

Try disconnecting the battery during service to "reset" the computer.

I hope that there's a less-drastic resolution to the trans light problem than "sell it"! My daughters 325is is showing the light with increasing frequency. Shutting down sometimes works, sometimes doesn't.

^

Originally Posted by boneweed

I hope that there's a less-drastic resolution to the trans light problem than "sell it"! My daughters 325is is showing the light with increasing frequency. Shutting down sometimes works, sometimes doesn't.

pay for a service, or put a lil elbow grease into it, or you could always pay to replace it.

Originally Posted by bmw-mania

Try some good ol' fashioned maintenance first..
Check, inspect, and replace as necessary.
Check the fluid, Flush fluid, change filter, refill with good fluid.

Try disconnecting the battery during service to "reset" the computer.

Originally Posted by loki13

trans oil for life? Who was the marketing genius behind that lie!

Originally Posted by jonesin

I'll be nice.
This car is autotragic. On these cars that means that it was made in France by GM, and had a badge slapped on it saying "Lifetime transmission fluid". This caused all kinds of issues. Hence the only good autotragic BMW is from Europe and was on the M3 made by ZF.

http://www.bimmerfest.com/forums/sho...d.php?t=638253

Guess I'll try changing the fluid this weekend. Anything to watch out for? I know it has to be level, there's 2 sumps, and it has to be a certain temp to top it off. I also need to see if it has the "lifetime" oil.

Ignore the "lifetime" fluid nonsense. That was a marketing gimmick that's cost many a BMW owner huge transmission replacement bills.

Do you suppose I can just drain the sumps and refill with new stuff or should I remove the sumps and change the filter(s) and gaskets?

You have to take the small sump off to drain it anyway. Pull both, clean them really well, absolutely change the filter and use new gaskets, then reassemble. You'll be wasting your time otherwise.

Pelican DIY in case you hadn't seen it already:

http://www.pelicanparts.com/bmw/tech...Fluid_Auto.htm