Cadillac Jim Posted September 14, 2007 Report Share Posted September 14, 2007 P0741 TCC System Stuck Off The TCC is the Torque Converter Clutch. You may notice that when you cruise over 40 mph, the tach settles down and the RPM tracks the speedometer, not the throttle. That's the TCC. By taking the torque converter out of the drive train, it gives you better gas mileage, particularly at highway speeds. P0741 means that the TCC isn't responding to the solenoid signal. This isn't a sensor replacement, it's a solenoid replacement. There are other people here who have more experience with the 4T80E than I do, but the usual advice is to leave it alone unless that additional 1 mpg or so is really important to you. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
drew51074 Posted September 15, 2007 Author Report Share Posted September 15, 2007 ok, i've done it now. i replaced the aftermarket t-stat with the OEM t-stat. i also replaced the temp switch on the head for the fans. filled her up with coolant and took her out for a spin. 210*. i think all is good for a while but i start to hear this rubbling sound. at first it sounded like a blown shock absorber or something, then it starts to get lounder and more frequent. then i notice im still hearing it even when im not moving. mind you the temp never goes past 210*. i pulled her over, pop the hood and the overflow tank is gurgling like crazy!! no steam or overflow, just a loud constant bubbling sound. loud as hell. WTF is that??!! she wasnt overheating according to the temp gauge, and the fans werent on either. should they have been running by this temp? or do they come on at a higher temp like what was previous stated? 224 for a low fan speed, and 229 for a high fan speed. i took a towel and folded it a couple times and opened the the rad cap and it was straight steam coming out. no water. did the engine drink all that water? i didnt notice any trail of water behind me when i drove in to the parking lot. i used the water hose at the gas station where i had stopped and it was darn near empty. the water wouldnt go down at first, but after a while it started taking it in. while i was pouring the water in a heard this loud knock come from the engine. i thinking aw man, i just cracked the block or something. i continue filling it with water til its full and i drive her home. 210* all the way home and she starts the gurgling again. i just shut her down and came inside. im thinking that annoying service engine soon light wasnt as bad as i thought. maybe i should have let well enough alone. i dont know. i'll check her out in the morning. she'd way to hot to do anything now. anyone have any ideas?? oh and another thing. before i came inside i noticed water leaking down form what looked like the side of the engine towards the firewall. please tell me there is a hose or something there were water can leak from. like a small heater hose or something i hope i didnt crack the block when i was refilling it. i turned the engine on before i started pouring the water back in. the fans have yet to come since i installed the new temp switch. where do i go from here?? im thinking im goin to put everything back the way it was and pray i didnt cause anymore permanent damage. that would just suck. she was running real good til now. all this over a darn check engine light i couldnt ignore. Link to comment Share on other sites More sharing options...
drew51074 Posted September 15, 2007 Author Report Share Posted September 15, 2007 P0741 TCC System Stuck Off The TCC is the Torque Converter Clutch. You may notice that when you cruise over 40 mph, the tach settles down and the RPM tracks the speedometer, not the throttle. That's the TCC. By taking the torque converter out of the drive train, it gives you better gas mileage, particularly at highway speeds. P0741 means that the TCC isn't responding to the solenoid signal. This isn't a sensor replacement, it's a solenoid replacement. There are other people here who have more experience with the 4T80E than I do, but the usual advice is to leave it alone unless that additional 1 mpg or so is really important to you. i called the caddy dealership about this code and the said that if its not fixed the tranny will be destroying internal parts the longer i drive it that way. now i know the dealers like to make stuff sound worst than it really is, but is there any truth to this? im not worried about the MPG. its good enough for me at 20 mpg. i just dont want to destroy my tranny. Link to comment Share on other sites More sharing options...
Ranger Posted September 15, 2007 Report Share Posted September 15, 2007 Bubbling in the tank means that air is being purged. The question is, where is this air coming from? Might (hopefully) be from you opening up the system. There are 2 coolant lines that run behind the rear head for the heater core I believe. They are a *smurf* to change though. Perhaps that is where the leak and air intrusion is coming from. Fans will not come on till 224 degrees. Link to comment Share on other sites More sharing options...
Ranger Posted September 15, 2007 Report Share Posted September 15, 2007 Many people have reported driving for year with P0741. All it means is that there is no TCC lock up, thus there is some minor slippage. I don't think you will be destroying any internal parts. See if others who are more transmission savvy than I agree. Link to comment Share on other sites More sharing options...
winterset Posted September 16, 2007 Report Share Posted September 16, 2007 Sounds like you didn't add any antifreeze in the radiator - only water. that'll explain the gurgling & steam. You ned to add 50/50 dexcool. You cannot perform any diagnostics without a 50/50 mix. Link to comment Share on other sites More sharing options...
drew51074 Posted September 16, 2007 Author Report Share Posted September 16, 2007 when i first did all the work replacing the t-stat and the sensor, i drained the cooling system and replaced it with the 50% dexcool and 50% water. after it started gurgling i filled her back up just water. she is still boiling over at 210* and i havent figured out why yet. im going to jump the wires again to the fans and see what happens. Link to comment Share on other sites More sharing options...
Ranger Posted September 16, 2007 Report Share Posted September 16, 2007 Forget the fans. Water doesn't even boil till 212. If it is actually boiling, you cap is not holding pressure. If false boiling, that is exhaust gases entering the system and pushing the coolant out the over flow. I think you need to have the coolant tested. Link to comment Share on other sites More sharing options...
drew51074 Posted September 17, 2007 Author Report Share Posted September 17, 2007 Forget the fans. Water doesn't even boil till 212. If it is actually boiling, you cap is not holding pressure. If false boiling, that is exhaust gases entering the system and pushing the coolant out the over flow. I think you need to have the coolant tested. i did a hydrocarbon test on the coolant. it came up negative. i think its a leaking heater hose between the engine and the firewall. im taking to my friends 10 min oil change shop so i can drive it over the "pit" and see where the water leaking from. i noticed a puddle of water towards the drives side under the engine a couple days ago when she started over heating or boiling over or whatever the hell she's doin now. from my experience if it was a combustion chamber leak into the cooling system when i shut the engine off the water and or bubbles would stop pushing out of the radiator cap. this didnt happen with this car. i shut her down. released the pressure on the overflow tank and it spewd steam for about a minute or so. then when it stop i tried to fill it and the water just got pushed back out by more steam. then i started the car and tried again. same thing for a while and then she started taking the water. the temp gauge never went past 210* the whole time. Link to comment Share on other sites More sharing options...
Ranger Posted September 17, 2007 Report Share Posted September 17, 2007 OK, this thread has gone for so long I forgot what you did and didn't do. Sounds like you have a leak that needs to be addressed. Link to comment Share on other sites More sharing options...
drew51074 Posted September 17, 2007 Author Report Share Posted September 17, 2007 Forget the fans. Water doesn't even boil till 212. If it is actually boiling, you cap is not holding pressure. If false boiling, that is exhaust gases entering the system and pushing the coolant out the over flow. I think you need to have the coolant tested. i also replaced the cap with a 16lb vented cap, if it did boil over or what its doin again i can just pull the vent lever and release the pressure out through the overflow hose instead of tryin to open the actual cap. Link to comment Share on other sites More sharing options...
Ranger Posted September 18, 2007 Report Share Posted September 18, 2007 But remember, releasing pressure lowers the boiling point. Link to comment Share on other sites More sharing options...
drew51074 Posted September 18, 2007 Author Report Share Posted September 18, 2007 But remember, releasing pressure lowers the boiling point. ok, you lost me. releasing what pressure?? the vented cap im talking about is the Stant radiator cap with the big red lever on top so you can release the pressure out of the cooling system in the case of overheating. it isnt meant to be left open when driving or anything, just a safer way to open the cap without getting burnt. the cap is rated at 16lbs. do you mean that pressure rating is too low?? is the stock cap set at a higher rate than that?? Link to comment Share on other sites More sharing options...
Ranger Posted September 18, 2007 Report Share Posted September 18, 2007 the vented cap im talking about is the Stant radiator cap with the big red lever on top so you can release the pressure out of the cooling system in the case of overheating. it isnt meant to be left open when driving or anything, just a safer way to open the cap without getting burnt. OK, we're on the same page. the cap is rated at 16lbs. do you mean that pressure rating is too low?? is the stock cap set at a higher rate than that?? Nope, you have the correct cap. Link to comment Share on other sites More sharing options...
drew51074 Posted September 25, 2007 Author Report Share Posted September 25, 2007 ok. new problem. what would cause the temp gauge not to show the actual temp whne it goes past 194*. i've been gone for a week and my old lady couldnt resist driven the caddy and she definately overheated today, but she said the temp gauge never went past 194*?? does that fan switch sensor serve another purpose besides turning on the fans?? Link to comment Share on other sites More sharing options...
BodybyFisher Posted September 25, 2007 Report Share Posted September 25, 2007 This is very good, check for codes, its possible that you have a bad coolant sensor. If the PCM 'thinks' the coolant is ONLY 194, it won't turn on the cooling fans... Keep in mind however that when the AC is on, the fans are commanded on... Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
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