Those QDM codes and tranny switch codes may be related. Try cleaning the [only] trans connector. It'* located in the front of the engine, on the trans, near the vacuum modulator. It'* a circular connector.. 6pins? Something like that. plug and unplug 10 times and throw a dab of dielectric grease on there for good measures.

The code 23 could be that the ECU isnt' talking with the IAT, making it read low [I believe the ECU'* default reading is -40*F or so.. which I believe could be considered low ]. Plug and unplug the IAT sensor [located in the airbox, the only sensor in it, and it'* under the airbox, accesable without removing airbox], and throw some dielectric grease on it too.

Easiest things first, check back with an update.

How did you get rid of the 3?

Replaced the (very expensive) TPS... that was a PITA to get out and back in... looks nice and simple, bit it took me almost an hour before I could start setting it properly... where as the rad fan sensor only took me 20 mins, and looks like it should be much harder...

I'll go and give those a shot, opensource... back in a bit with a reply...

Ok, cleaned the tranny plug (note to self, when its -4oC, be very carefull with the clips on the plugs, they become very brittle ) and put some dielectric grease on it, and found the MAT sensor, and plugged it in (the sensor wasn't even connected.. and I'm assuming that its the MAT that is in the airbox, no?)

So, I jump in the car, turn it on, and NO SES!! WOO WOO!! So I take it for a test drive, and after about 2-3 mins, the SES came back on.. I would assume that its still the QDM and the tranny switch code... not sure yet, as I haven't reset the codes to pull fresh ones... I did pull the codes after my test drive, and they were the same 3, 23, 26, and 27... so obviously these computers don't erase the codes that have been repaired...

But it was nice not seeing that damn SES light for a change, even if it was only for a couple of mins.. I did notice though that the light doesn't come on at a specific time though... not during a shift, not during a down-shift, not during WOT, ect...

There is no Mat sensor ,there is a Maf sensor that is the black rectangle thing beside TPS.The one in the air box is IAT (intake air temp) i am assuming you are talking about this one.Did you disconnect battery while you replaced TPS as this probably should have erased the codes that are repaired.Battery disconnected for 15mins -30 mins should erase fixed codes.Is your filter in air box old maybe it is clogged up .

Try disconnecting the battery for ~30min, to reset the codes. Then before starting the car, check the codes. You shouldn't have any [just to make sure]. Fire up the car, and recheck.

That SES light sure is annoying isn't it? All those darn idiot lights are annoying.. they are like full fledged interiour lights, in the form of annoying colours.

jdq is right, there is not "MAT" sensor, but that is the same as an IAT sensor, which is what we have.

I highly doubt a clogged filter could cause a low temp reading, that'* usually a sign of a sensor/wiring issue. What about captainmiller who sees -40*C temps during the winter, and i'm sure he doesn't get a low temp code... and -40*C is pretty cold IMO.

Ya your right OSG just trying to think of something to help, why would he not of had that code in the first place if it ( IAT )was unplugged all the time.Also Cyrics had afew posts with lots of codes and wiring problems , it does seem like there are more to the codes .Cyric are you sure the Tps is calibrated properly.Also doesnt the Quad relate to a few things like fan relay , tcc solonoid , Egr and couple other things..

Well, the reason why I call it a MAT sensor is because that is what its called in the FSM... but, tomatoes - tomatoes..

I did reset the codes after I installed the TPS, and I set it to about .39 volts.. within the range required in the FSM .36V - .43V I think)

I think the IAT didn't register a code because the TPS was out of whack... so that over-rode it.. I don't think I'll have time during the week to clear and re-check the codes, because now my boss says we have work again.. which is a good thing...

I know that the TPS relates to the QDM, which relates to the gear shift switches... but what confuses me is, why when I cleard the codes after replacing the TPS, did the 4th gear switch, and the TCC codes dissapear? I can understand the IAT code being thrown, but why the 2 codes dissapear, and not the other 2...

Welcome to the wonderful world of electronic gremelins. Could be anything, dude.

jdg: no idea why it didn't throw the code earlier, could have been it was connected and now it'* not, or like cyric said with the TPS failure the ECU just got confused.

Well, I managed to pull the code this evening... One left!

Code 26 still... QDM... I know I got the car into 3rd gear after I reset the codes, so the code 27 didn't show itself...

With these gear shift codes, are they solenoids that are supposed to be malfunctioning or what? Is it all internal in the tranny that there is problems with those sensors? I'm wondering if my tranny fluid change fixed those 3 codes (27, 29 and 39)