Wild.Bl Posted March 8, 2019 Report Share Posted March 8, 2019 (edited) I was having an intermittent "Check Engine" light showing P0171. Connected my diagnostic tool and found very high (38+) LTFT at idle that would slowly decrease at higher RPM to (25). Started by checking for vacuum leaks and this is what I found. PVC hoses cracked and brittle (see pictures). Temp fix with duct tape while waiting for a new replacement from AC Delco. Better already with less fuel consumption! Hope this helps others. Edited March 8, 2019 by Wild.Bl Quote Link to comment Share on other sites More sharing options...
Wild.Bl Posted March 8, 2019 Author Report Share Posted March 8, 2019 Sorry posted wrong year! It's a 2013 !! Quote Link to comment Share on other sites More sharing options...
cdgrinci Posted March 10, 2019 Report Share Posted March 10, 2019 Glad you found the problem but I think some electrical tape would have worked better and looked a lot nicer. Just throwing out my two-cents (and it's probably not worth that). Quote Chuck '19 CT6, '04 Bravada........but still lusting for that '69 Z-28 Link to comment Share on other sites More sharing options...
BodybyFisher Posted March 13, 2019 Report Share Posted March 13, 2019 Good catch. Interesting that is a 4 cylinder and the lean code is P0171, but there is only one bank. Lessons learned everyday. Maybe on the 2.0 the P0171 doesn't designate any banks, just lean condition. Let us know how it runs after replacing the pipe. 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...
davism4 Posted March 14, 2019 Report Share Posted March 14, 2019 This was my car. Couldn't remember my login info so had my dad post it. we found the problem in my parking lot and the only tape I has was the duct tape. Once applied it ran much better. Hasn't set any codes in the last week so the temp fix worked. On my way now to pick up new parts. Will update after. @BodybyFisher you are correct, the only way we figured it out before looking was looking at my obd2 scanner and a very high LTFT and saw that the manifold pressure was staying steady (really high) with throttle open AND closed. So we knew it was a vacuum leak. The split in one end of the line was so big that using carb clean to find it, it didnt even get an rpm rise. It was only when my (bad) eyes saw it that it all made sense. Quote Link to comment Share on other sites More sharing options...
BodybyFisher Posted March 14, 2019 Report Share Posted March 14, 2019 1 hour ago, davism4 said: This was my car. Couldn't remember my login info so had my dad post it. we found the problem in my parking lot and the only tape I has was the duct tape. Once applied it ran much better. Hasn't set any codes in the last week so the temp fix worked. On my way now to pick up new parts. Will update after. @BodybyFisher you are correct, the only way we figured it out before looking was looking at my obd2 scanner and a very high LTFT and saw that the manifold pressure was staying steady (really high) with throttle open AND closed. So we knew it was a vacuum leak. The split in one end of the line was so big that using carb clean to find it, it didnt even get an rpm rise. It was only when my (bad) eyes saw it that it all made sense. Well that is a good find and good information for other members going forward, so thank you for sharing this here. Its a shame that a connector like that j u s t gets beyond 5 years, this is stuff that GM needs to see and stop from happening going forward, it looks like they are wedded to planned obsolescence. Now in their defense, this tubing COULD have been damaged during service or physically stressed causing the problem, but if this is becoming a problem and we see this again, I would alert GM. While the first owners may keep the car a few years, its the second and third owners experience that will kill a reputation. 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...
djQ Posted November 19, 2019 Report Share Posted November 19, 2019 (edited) What was the part number of the hoses and where did you buy the replacements? @Wild.Bl @davism4 Edited November 19, 2019 by djQ Quote Link to comment Share on other sites More sharing options...
djQ Posted December 3, 2019 Report Share Posted December 3, 2019 What was the part number of the hoses and where did you buy the replacements? @Wild.Bl @davism4 Quote Link to comment Share on other sites More sharing options...
Nivay Posted February 4, 2020 Report Share Posted February 4, 2020 I have the same problem but i still have high LTFT. Make sure you check the little hose/tube next to it too because mine was broken too. I also changed the spark plugs and cleaned the MAF sensor it was really dirty. I just finished a few hours ago so we'll see what happens in a few days. The part numbers for tubes/hose: 12673868 and 12681589 Ohh yeah i have a 14 ats 2.0t 110k miles Quote Link to comment Share on other sites More sharing options...
Santoszach9 Posted February 6, 2020 Report Share Posted February 6, 2020 Can’t quite narrow down the answer I have a 2015 Cadillac ATS 2.0 and nothing really seems to narrow it down where Are common air leak spots? My air filter isn’t saturated with dirt but is a little dirty grey I believe it’s still okay and my car is a 2015 it wouldn’t be the spark plug my car is almost to 60,000 miles on it and I don’t believe it’s had it’s first tune up would that Cause Po171 to trigger? I need more possibilities please help. Quote Link to comment Share on other sites More sharing options...
Jonathan D1970 Posted October 30, 2020 Report Share Posted October 30, 2020 Thanks so much for this post. I have replaced the MAFS and the Camshaft Position Actuator Solenoids. But, the check engine light kept coming back on. I removed the cover and noticed a small crack in my lines also. Hopefully this will finally fix a headache of mine for the last year. Quote Link to comment Share on other sites More sharing options...
djQ Posted November 5, 2020 Report Share Posted November 5, 2020 On 10/30/2020 at 3:42 PM, Jonathan D1970 said: Thanks so much for this post. I have replaced the MAFS and the Camshaft Position Actuator Solenoids. But, the check engine light kept coming back on. I removed the cover and noticed a small crack in my lines also. Hopefully this will finally fix a headache of mine for the last year. @Jonathan D1970 did that fix your problem? Quote Link to comment Share on other sites More sharing options...
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