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Registered
Join Date: Dec 2003
Posts: 3
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93 328i auto tranny, no downshift at stop
Since the weather has turned colder, my auto tranny sometimes doesn't take off from 1st after a stop or after slowing way down. When this problem occurs, it seems to try and take off in 3rd, although lately it seems to take off in 2nd.
I replaced the "A/M" or "E-H" switch on the console and that didn't seem to have much of an effect on the frequency of occurance. I've checked the plugs on the transmission and engine control modules and it all looks like a good connection. I don't get any problem codes or idiot lights associated with the non-downshifting. After searching the web, I found where someone corrected their similar problem by replacing the throttle position sensor (TPS). I checked mine and the resistance smoothly changes from 1.5 to 4.5 kOhm. Bentley says is should be approx. 1 - 4 kOhm. Before I purchase another TPS, does anyone have similar experiences or recommendations for solution? (BTW I used the pelicanparts.com web page on e36 transmission service to service my tranny several months ago--everything worked out great. Thanks for the excellent service information!) --93 325i, auto, stock, 119,000 miles |
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12-03-2003, 04:36 PM
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Join Date: Dec 2003
Posts: 3
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Just a follow up in case someone else out there is googling about this problem. I replaced the throttle position sensor (TPS) and that cured the problem for about 7 months. The no downshifting problem recurred and I again replaced the TPS but the problem remained. From my own googling around the net I found a few references to this problem being related to the ECU on the transmission control unit and that there is a service bulletin on this. The stock ECU is only available from the dealer as far as I know, but I think Dinan sells a "hi-perf" one for ~$200. So, I took the car to the dealer who troubleshot the problem and with my consent, replaced the ECU. This has apparently fixed the problem. The ECU was about $20 but the labor costs brought it back to $200. If you want to DIY, you could just get the Dinan tranny chip.
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08-27-2004, 05:14 PM
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Registered
Join Date: Nov 2003
Location: Columbus, Oh
Posts: 57
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Is the ECU chip in a socket or is it soldered to the PCB?
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1998 323is, stock, auto, Sport pkg, Hellrot/314, 88k miles |
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08-30-2004, 09:23 AM
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