Bob Smith Posted January 23, 2015 Report Share Posted January 23, 2015 Hello, I am new here but have cruised the site for a while. My problem is 2 fold and I have heard they may be related though I am not sure how. My cars transmission has gone into some kind of limp mode, no codes. No first, second?, lock up. Reverse and 3rd ok, slight delay shifting into r or d from park. This happened out of the blue, one day its fine next morning its sick. 2nd problem, I have a current P038, P036 codes. the 036 is because the egr valve is disconnected, has been for a year, the P038 looks up to be the AIT sensor which I can not find in the car. There seems to be some confusion about this engine, I read about it and people say the intake cover is part of the system but mine is not, it is ornamental so either my engine has been updated/replaced or maybe built late enough in the model year to have the 95 intake system I do not know. I bought this car 14 months ago, body is nice and it rides pretty good, too bad it has to act up now when its cold and snow is coming, this is my everyday ride and I need it to get around. This is my second Caddy, the first was back in 69 so my knowledge about them is slim and I really need your help. Thanks, Bob S Link to comment Share on other sites More sharing options...
Logan Posted January 24, 2015 Report Share Posted January 24, 2015 It is actually called the IAT sensor. Logan Diagnostic LLC www.airbagcrash.com www.logandieselusa.com www.ledfix.com www.ledfix.com/yukontaillightrepair.html www.ledfix.com/ledreplacements.html www.ledfix.com/j42385toolrental.html Link to comment Share on other sites More sharing options...
Logan Posted January 24, 2015 Report Share Posted January 24, 2015 Another pic..both pics are for the 1994 intake. Logan Diagnostic LLC www.airbagcrash.com www.logandieselusa.com www.ledfix.com www.ledfix.com/yukontaillightrepair.html www.ledfix.com/ledreplacements.html www.ledfix.com/j42385toolrental.html Link to comment Share on other sites More sharing options...
Bob Smith Posted January 24, 2015 Author Report Share Posted January 24, 2015 It is actually called the IAT sensor. LOL even spelled correctly, I still can't find it... First Thank you for the reply and pic, unfortunately that pic is not my engine, that one, the cover is part of the intake, mine is only an ornament. According to the vin, the engine is a 94 Northstar 4.6 ld8. Tranny Update. After checking wiring and fuses I decided to clear the pcm by disconnecting the batt for 20 minutes. It did not help, my test drive started out in 3rd as far as I can tell (shifter in D). While traveling at 30 mph I shifted to 3 then to 2. It was like putting on the brakes! I pulled over on a slight decline and with the car in 2 it would not roll, in fact with the engine at 2000 rpms it was still stationary as if the brakes were on, I put it into d and off it went, put it in 2 and the brakes came back on. I disabled the traction control unit and tried it again, this time the brakes did not come on. After coming to a stop on the way home, the car shifted into First and proceeded to shift normally for the rest of the way ( about 1 mile). What the heck? Stuck solenoid? Problem with traction control affecting the Trans control? Maybe a real good time to sell? Nah, couldn't do that.. Link to comment Share on other sites More sharing options...
Logan Posted January 24, 2015 Report Share Posted January 24, 2015 Hmm...don't know. Trying to install a latter engine or intake would be risky. They did move the IAT sensor on the latter cars to the air cleaner assembly. See attached picture from a 1996 model. Sorry..no 1995 info available on my end. That could be why there is a code for the IAT sensor. Logan Diagnostic LLC www.airbagcrash.com www.logandieselusa.com www.ledfix.com www.ledfix.com/yukontaillightrepair.html www.ledfix.com/ledreplacements.html www.ledfix.com/j42385toolrental.html Link to comment Share on other sites More sharing options...
Bob Smith Posted January 24, 2015 Author Report Share Posted January 24, 2015 Hmm...don't know. Trying a install a latter engine or intake would be risky. They did move the IAT sensor on the latter cars to the air cleaner assembly. See attached picture from a 1996 model. Sorry..no 1995 info available on my end. That could be why there is a code for the IAT sensor. This is nuts! my air cleaner has no hole nor does it have the sensor. First place I looked as it is the most sensible placement. (my opinion). When the snow melts I am going out and pull the cleaner out and tear that section apart to see if there is a harness buried near it. Perhaps there was one and for some strange reason it is gone and the housing either replaced or patched so I did not notice a hole. I bought this car from a garage picker, guy goes around finding cars and stuff, cleans them up and sells them, It had sat in a garage for 10 years. He did basics to get it saleable, including having to replace the coil packs and part of the coil/egr harness. Who knows what he may have cut out, the wire harness he used was from a different year. I did correct that part of the wiring last summer. I knew what I was getting when I discovered I had to press a switch to engage the starter, I also fixed that problem by replacing the relay. Thanks again! Link to comment Share on other sites More sharing options...
Logan Posted January 24, 2015 Report Share Posted January 24, 2015 It's either one or the other. Technically....the IAT sensor just has to sit in the incomming air stream. If the engine really has a different intake...It could be cable tied to the harness outside somewhere....or maybe just dangling there... The engine would run.. You could go in and look for the sensor with a scan tool or thru the cluster (IPC) diagnostics. A missing sensor will display -40 degrees F. On the original 94 intake...some disassembly has to be done to get to the IAT. I highlighted the previous picture. It is next to the MAP sensor. Logan Diagnostic LLC www.airbagcrash.com www.logandieselusa.com www.ledfix.com www.ledfix.com/yukontaillightrepair.html www.ledfix.com/ledreplacements.html www.ledfix.com/j42385toolrental.html Link to comment Share on other sites More sharing options...
Bob Smith Posted January 25, 2015 Author Report Share Posted January 25, 2015 It's either one or the other. Technically....the IAT sensor just has to sit in the incomming air stream. If the engine really has a different intake...It could be cable tied to the harness outside somewhere....or maybe just dangling there... The engine would run.. You could go in and look for the sensor with a scan tool or thru the cluster (IPC) diagnostics. A missing sensor will display -40 degrees F. On the original 94 intake...some disassembly has to be done to get to the IAT. I highlighted the previous picture. It is next to the MAP sensor. Thanks Logan, I am going out soon to clear off the snow and check for a harness connector. I am getting a -40 code so I assume it is missing or maybe faulty, the engine does run but fuel economy and performance could be better. I located pictures of similar intakes however I cannot attach them to the post but I included a link to one showing the type of intake and location of at least the Map and the plastic fuel rail. http://www.google.com/imgres?imgurl=http://i826.photobucket.com/albums/zz183/billytheshoe/northstar%252520hijacked%252520pics/de18e8ad-1.jpg%253Ft%253D1327027429&imgrefurl=http://www.cadillacforums.com/forums/cadillac-seville-cadillac-eldorado-forum/250075-cadillac-seville-1995-sls-revving-itself.html&h=509&w=638&tbnid=qjp3hmWE2VlgYM:&zoom=1&docid=P7eXIUrz6uIJhM&ei=sA7FVI_2ItG1sATv44D4Dg&tbm=isch&ved=0CCEQMygAMAA I hope posting this link does not break any rules Link to comment Share on other sites More sharing options...
Logan Posted January 25, 2015 Report Share Posted January 25, 2015 Ouch....it's either a different intake or different engine. That is not a '94 intake. Sounds like the wiring been cobbled up to make it work...sort of...with no IAT sensor. Let the fun begin... I would suggest checking the VIN number stamped on the engine block. That would sort out the issue of are you dealing with a different engine or just a different intake. Stupid question....how sure are you it is a '94? Production of '95s would have begun in July '94. So the door sticker may show 07/94...but the car would be a '95 model. Logan Diagnostic LLC www.airbagcrash.com www.logandieselusa.com www.ledfix.com www.ledfix.com/yukontaillightrepair.html www.ledfix.com/ledreplacements.html www.ledfix.com/j42385toolrental.html Link to comment Share on other sites More sharing options...
Bob Smith Posted January 26, 2015 Author Report Share Posted January 26, 2015 Well yesterday was interesting. I pulled the intake cover and searched again but only found a leaking fuel pressure valve, of which they seem to list about 8 different ones. Pulled the air intake housing, on the bottom under the filter there is a 1 inch hole that looks like it never had anything in it. Searched but did not find any unused 3 wire connectors, except one on the passengers side of the engine, near the heater core (I doubt that is it). If I can find the correct wires in the correct harness, maybe I can make up something. When the weather breaks I am heading to the bone yard, a few still have some late 90's in them. I am thinking I need an OEM wiring harness diagram for 94 and possible 95, My vin number is 1G6KF52YXRU302010 the Y is LD8 correct the build date is 05/94 making it a late 94 model. Did GM Dealers log cars into a database by serial number in the 90's and early 2000's ? Thanks again for your help. Link to comment Share on other sites More sharing options...
Logan Posted January 26, 2015 Report Share Posted January 26, 2015 On all of GM. The IAT sensor is just a 2 wire sensor. The 2 wire colors are tan and black in the 1994 service manual. Logan Diagnostic LLC www.airbagcrash.com www.logandieselusa.com www.ledfix.com www.ledfix.com/yukontaillightrepair.html www.ledfix.com/ledreplacements.html www.ledfix.com/j42385toolrental.html Link to comment Share on other sites More sharing options...
Bob Smith Posted January 27, 2015 Author Report Share Posted January 27, 2015 My mistake, I thought I saw a wiring diagram with 3 , red/black/grey for it but I haven't seen a 2 wire connector either. Right now its of little concern as we have 2 feet of fresh blowing snow to deal with. I have a feeling that the guy I bought it from has cut or stuffed it somewhere out of sight, this guy removed the intake to hot wire the starter solenoid so anything is possible. I guess we can close out this post till spring Thanks for your help. Link to comment Share on other sites More sharing options...
barczy01 Posted January 30, 2015 Report Share Posted January 30, 2015 Pull the main transmission connector apart and make sure its clean. Link to comment Share on other sites More sharing options...
Bob Smith Posted January 30, 2015 Author Report Share Posted January 30, 2015 Pull the main transmission connector apart and make sure its clean. I intend to do this as soon as enough snow has melted enough so I can work on it. It is running fine right now ??? go figure! I had disabled to traction control and it started working after 1 mile and coming to a stop. Since after 11 restarts the traction control is active again and utilized once, the tranny is still functioning correctly. It does have a P 029 I'll have to check to see if it is active or moved to history. This leads me to believe it is electrical. Link to comment Share on other sites More sharing options...
winterset Posted January 30, 2015 Report Share Posted January 30, 2015 Massachusetts!! Can you even get out of your house yet. I believe you are getting more snow this weekend. Yes, wait till the summer when some of the snow melts. Link to comment Share on other sites More sharing options...
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