just found the following
http://forum.e46fanatics.com/showthread.php?t=827839
Join Date: Mar 2009
Location: Depends on the day
Posts: 90
My Ride: LSB E46 M3
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New Solution for the SMG problems (potentially)
Hey everyone
I may have potentially found a new cure to SMG problems. My 2002 LSB M3 (in the sig) was dropping out of gear while driving, and going back in 5 seconds later. I took it to the dealer, and two other shops, and they diagnosed it as the pump. However, I refused to believe that because it was shifting perfectly (when it wasn’t going out of gear), and it was priming just fine. So after A lot of research and reading numerous threads, I came across a few that mentioned the temperature sensor on the SMG unit possibly malfunctioning. However, I did not find anyone who actually attempted a replacement. So, I did. I ordered the part, took it to a local shop, and replaced it. Also, I lost some fluid, so we added some fresh Pentosin, primed the system, and so far, I am 200 miles trouble free. I am continuing to drive it to test this fix, so stay tuned.
The part number is 13-62-1-709-966
Lets refer to this fix as the MOZE fix (my initials) lol.
and
I have found the cause of this horrible flaw of the SMG transmission issue and it leads to the Pump temp sensor being mounted way too close to the engine. As a result, while you are sitting in traffic (with no airflow to cool it off it gets hotter and hotter) the HYD Pump temp sensor picks up heat from the engine and sends a signal to the ECU telling it the HYD fluid is "too hot." This is not the actual case. The result is the circuit that tells your pump to charge the accumulator is momentarilly disabled. You have two or 3 shifts left in the accumulator and after that there is not enough pressure to make the next gear so it drops to nuetral. after about 15-30 seconds the circuit is momentarilly restored and the accumulator charges again...the cycle repeats over and over again untill you can get on the highway or just simply shut the car off and let it cool for at least half an hour.
To stop this problem from happening i experimented and read through schematics for 3 days and what i came up with worked for me and it also worked for another member of this forum whom i was sharing ideas with. The best part is it it costs about 5 bucks if you do it yourself.
Take a 500-1K ohm heat resistant resistor and splice it in series with the temp sensor. its that simple. it takes about 20 Minutes start to finish. i waited about a week to post this to make absolutly sure the problem was gone. you can access the connector that goes from the ECU to the HYD pump from unterneath the car just "inboard" of the front driver side tire. there are 18 wires on it i think and all sorts of colors. the wire you want is the SOLID WHITE WIRE. Just cut it, splice in the resistor and wrap it up tight and your done.
Now keep in mind that this does not keep your car from heating up the actual sensor but instead, adds a temp "bias" for your ECU to not allow it to reach the over temp voltage. This in my opinion is safe, effective and a dream come true for the price. Remember, the only possible effect of hyd fluid over heating is premature wear of the pump itself...chances are if you have this problem, you were told you need to replace the pump by the mechanics for about $3500...Sounds like we have nothing to lose right? Especially since the hyd fluid isnt really overheating in the first place and its just the engine heating up the sensor that is aprox 3/4'' away from it.
KCCOusmc10 is offline
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now the car only acted up on the hottest days this week so am going take her for a spin and see:rollsmile:
