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1995 BMW 325i Transmission Control Module


MatthewNadeau's Avatar
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07-22-02, 01:48 PM   #1  
MatthewNadeau
1995 BMW 325i Transmission Control Module

Our 1995 BMW 325i seems to have a problem with the transmission control module. Yesterday, while my wife was driving, the car would downshift while she was driving (automatic transmission). She said she would slow down to normal RPM's, but when she picked up speed it would downshift again. I wasn't able to get it to repeat this, but the transmission control module error light came on when I got up to about 60 MPH. After I turned the car off, the error light went away and it hasn't come on since. It seems like the car is stuck in 3rd gear and it won't go into overdrive (4th?). As long as I keep it under 40 - 50 MPH, it drives fine. Any suggestions before I take it into a shop?

 
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07-22-02, 04:30 PM   #2  
Joe_F
Go to Autozone and see if they can extract any trouble codes from the computer. They do it free.

Tell us what you find.

 
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07-22-02, 06:57 PM   #3  
MatthewNadeau
They said that they can only get the codes when there is a "check engine" light on. I only got a gear sprocket symbol which indicates that there's some problem with the transmission control module. I haven't been able to get the indicator to come back on, but I've been hesitant to get above 3000 RPM, so that be the reason.

 
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07-23-02, 06:04 AM   #4  
Joe_F
It sounds like fault in the electronics of the tranmission. First thing I would do is find an import shop or dealer that can scan the codes (if any) and see what's going on in there.

 
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07-24-02, 01:24 PM   #5  
MatthewNadeau
Well, I took it into the repair shop today and they told me that when they took off the front oil pan, there were parts and other junk in the bottom of the transmission. He said that it looks like there isn't enough left to do a rebuild, so I'm getting a quote for a new transmission (probably >$3000).
This seems very strange especially since we only have 58,000 miles. Should I get a second opinion or try to determine how the failure occurred?

 
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07-24-02, 03:19 PM   #6  
Joe_F
Ask him to explain it, but it sounds plausible. Have you ever changed the tranny fluid? If not, that lack of upkeep was the likely cause of the failure.

 
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07-24-02, 06:08 PM   #7  
MatthewNadeau
We have maintained the car very well and the transmission fluid was changed about 10,000 miles ago. I talked with him a little more and he mentioned that there was a modification done to the BMW transmission that he thinks might have prevented this. He didn't give me any details on the modification, but he suggested that we go to the BMW dealership and see if they would cover the repair under warranty (it's only 8,000 miles out of warranty). I was tempted just to take it to a different dealer and trade it in without telling them about the problem, but I would rather that they just repair it.

 
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07-24-02, 07:40 PM   #8  
Joe_F
I would agree. There was probably an enhancement or TSB on the problem. Check www.alldata.com to find out and if so, fight with the BMW dealer for partial or full remibursement.

Your mechanic is right on.

 
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07-24-02, 10:24 PM   #9  
MatthewNadeau
I can't access the TSB's, but there are several dealing with A/T problems. I checked on another BMW forum, and there were several questions relating to the integrity of the tramsmission control module. What are the chances that the TCM is bad and that the transmission is OK? He said that there was metal in the oil pan (although I didn't get to see it), but does that necessarily mean that the transmission is shot?

 
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07-25-02, 03:25 AM   #10  
Joe_F
What is his diagnosis? The TCM can be checked for fault with the proper tools.

 
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