I have my car in the shop cause my tranny was shifting hard Sunday and
Monday morning didn't want to shift for a while. My g/f's dad was checking
it out but couldn't find an updated manual for my car (97 Mitsubishi
Mirage; 4G93 SOHC; Automatic). He doesn't think it's anything physically
wrong with the transmission because the only time it doesn't shift is when
you moved it from Park to Drive or Reverse and it kicks hard. If it's
moved from Park to Drive or Reverse without the hard kick then the
transmission shifts fine. The car isn't throwing any error codes and he
cleaned the connections and checked the battery and alternator thinking
something electrical may be throwing off a sensor. Do you know where I can
get a diagram of the computer to tranny schematics? He's called around and
some people have said the computer may be causing the problem.
I checked the transmission oil and the level was fine. The tranny oil and filter is changed at least every 30,000 miles. I sometimes even did it at 15,000 miles. I've had the transmission fluid flushed once at 90,000 miles. The last oil/filter change was at 120,000 miles. It's not due for it's next maintenance till 150,000. Right now it's at around 135,000. The car is still being checked but right now it looks like it may be electrical or sensor related. Thanks for any help.
The only places I know of that will have the schematic you're looking for
is AllData, Mitchell1, the dealer or TRANStec. But from the description
you give it sounds like a stuck pressure relief valve or a weak/leaking
Don't let that throw you off. You're going about it the right way attempting to diagnose rather then jumping to conclusions. Let me ask you this. You said you pulled codes. Did you pull all proprietary and OBD II codes or just generic OBDII codes? If you just got the generic codes it won't tell you anything about the transaxle. Checking datastream while driving would be a great help as well.
The trans ecu has been checked and there are no codes at all. They're going to try replacing the Tranny ecu on a 3 day trial basis. If this works then I'll buy it otherwise I return it and pay a $30 fee. All connections have been rechecked, battery checked, and I forgot what but some $40 dollar module was replaced. Per the ECU people Mitsubishi computers are known to go out.
I'll get more info. later but changing the Ecu did not help. The Output/Input sensor was checked. The park/neutral safety switch was replaced. Several attempts to check the computer for a code have come up empty. I believe the next step will consists of looking inside the transmission. I'm not sure how they will do that since the Mirage doesn't have a traditional pan that can be dropped.
Maybe this will hope someone with the same problem in the future.
The problem was found. It was the Transmission Temperature sensor that was malfunctioning. This required also purchasing the Transmission wiring harness (which has been redesigned as well). These are located inside the transmission.
We appreciate you posting back. This is the kind of stuff these forums need so all of us can learn from each other.
Where is the transmission computer located in my mirage because it needs to be changed but i cant find it