SteveW Posted October 23, 2020 Report Share Posted October 23, 2020 I encountered an interesting phenomenon. I've had a hard P0741 fault for 3 or 4 years. When I cleared my DTC's the P0741 code would return immediately after 2 consecutive trips. I also had shifting problems. Additionally, I had intermittent hard shifts and the "chuggling" symptom at idle. I also had a vacuum leak from the intake to PCV valve hose line. Long term fuel trims were a consistent +19 to +20. I replaced the PCV hose line. When I started it, the engine stalled with a P0101 DTC. After some investigation, I found a damaged MAP sensor. The sensor stem had broken resulting in the MAP sensor over-reporting engine load and un-metered air entering the throttle body. I replaced the MAP sensor and this corrected the idle problem and the P0101 code. I checked the LTFT and they were back to normal levels. When I did the test drive, the P0741 did not set. I have driven about 100 miles since then, making 6 or seven trips over four or five days and the P0741 has not returned. I do regularly drive over 41 MPH and I've verified the RPMs drop when I'm in 4th and reach 41. Gas mileage is now around 19 MPG in town while it was in the low 16's before the repair. The transmission shifts normally now. rockfangd 1 Quote Link to comment Share on other sites More sharing options...
BodybyFisher Posted October 23, 2020 Report Share Posted October 23, 2020 This should be unrelated to a P0741. If it were due to leakage it wouldn't have been affected for sure. But maybe its possible during your investigation of the P0101 code you accidently reset or disturbed (in a good way) the main transmission plug improving its connection. The P0741 sets when the computer detects a greater than 250 rpm slip in the lock up torque converter. Within that main plug are connections for the TCC solenoid. Did you clean any grounds maybe? Keep us updated as to whether or not it comes back rockfangd 1 Quote 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...
rockfangd Posted October 24, 2020 Report Share Posted October 24, 2020 Intrigued here. Just out of curiosity when was the last time you checked the fluid level? When my Torque converter started to act up I would find that the fluid level would increase. Does it shudder at TCC lockup, Around 41mph. If you hang around 40, then slowly accelerate to 41 or so it might shudder before lockup. That is a telltale sign Quote GM FAN FOREVER Nice, clean, luxury= fine automobile Link to comment Share on other sites More sharing options...
SteveW Posted October 24, 2020 Author Report Share Posted October 24, 2020 20 hours ago, BodybyFisher said: This should be unrelated to a P0741. If it were due to leakage it wouldn't have been affected for sure. But maybe its possible during your investigation of the P0101 code you accidently reset or disturbed (in a good way) the main transmission plug improving its connection. The P0741 sets when the computer detects a greater than 250 rpm slip in the lock up torque converter. Within that main plug are connections for the TCC solenoid. Did you clean any grounds maybe? Keep us updated as to whether or not it comes back I don't think the PCV hose vacuum leak was related but, perhaps the damaged MAP was. The MAP on that car tells the ECU what load is on the engine. If MAP thinks the load is higher, the ECU would adjust shift points and RPM accordingly. When the car reached 41 MPH, the ECU turned on the TCC but, the engine speed was improperly elevated due to misreporting by the MAP. Maybe this tricked the ECU to think the elevated RPM was due to slippage. That's my theory anyway. Didn't touch TCU connections or grounds. BodybyFisher 1 Quote Link to comment Share on other sites More sharing options...
SteveW Posted October 24, 2020 Author Report Share Posted October 24, 2020 17 hours ago, rockfangd said: Intrigued here. Just out of curiosity when was the last time you checked the fluid level? When my Torque converter started to act up I would find that the fluid level would increase. Does it shudder at TCC lockup, Around 41mph. If you hang around 40, then slowly accelerate to 41 or so it might shudder before lockup. That is a telltale sign Just changed the fluid about 1K miles ago. The fluid change had no effect on the hard P0741 faults. It never has shuddered at lockup. It did occasionally "chuggle" at idle though. Quote Link to comment Share on other sites More sharing options...
BodybyFisher Posted October 24, 2020 Report Share Posted October 24, 2020 32 minutes ago, SteveW said: I don't think the PCV hose vacuum leak was related but, perhaps the damaged MAP was. The MAP on that car tells the ECU what load is on the engine. If MAP thinks the load is higher, the ECU would adjust shift points and RPM accordingly. When the car reached 41 MPH, the ECU turned on the TCC but, the engine speed was improperly elevated due to misreporting by the MAP. Maybe this tricked the ECU to think the elevated RPM was due to slippage. That's my theory anyway. Didn't touch TCU connections or grounds. That is interesting. Ill go into the manual and see if there are any related codes associated with a P0741, thanks Quote 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...
rockfangd Posted October 25, 2020 Report Share Posted October 25, 2020 Is the chuggle in gear or in park? I am thinking that the TCC would not attempt lockup without meeting the proper parameters. Could be wrong though. Quote GM FAN FOREVER Nice, clean, luxury= fine automobile Link to comment Share on other sites More sharing options...
SteveW Posted October 25, 2020 Author Report Share Posted October 25, 2020 23 minutes ago, rockfangd said: Is the chuggle in gear or in park? I am thinking that the TCC would not attempt lockup without meeting the proper parameters. Could be wrong though. In gear, at idle but, only occasionally. Chuggle is gone now. I thought the only conditions for lockup were, car in 4th gear and vehicle speed of 41 MPH. I'm not sure about that though. The persistent P0741 codes are gone. Only things I changed was the leaking PCV line and the damaged MAP sensor. Quote Link to comment Share on other sites More sharing options...
SteveW Posted October 26, 2020 Author Report Share Posted October 26, 2020 (edited) Found a vid with a mechanic talking about TCC problems with MAF codes present. He talks about it around 1:20. https://www.youtube.com/watch?v=1Ra-H1xSPLc Edited October 26, 2020 by SteveW Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.