Manifold air pressure too high under deceleration Time to start digging. Recommendations appreciated.
Stop decelerating! Not sure on this one. Sorry. Just off the top of my head could it be a clogged exhaust or bat cat?
Me. (raises hand) I've had bat problems and I've had cat problems but I don't think I've ever had a bat cat issue. Nor do I have, I assume, a bad cat. Anyone heard of that being a potential P1109 cause? Guess I'll go Google that... Pretty much everything I've read so far says it's a bad crank pulley. Apparently there were flaws in the design of the early Gen1 pulley and since my R50 is more than 14 years old I'd say the finger points to my needing to replace it anyway. I'm willing to go that route but given I need to spend as close to zero dollars as possible right now I'd like to be sure there aren't other potential causes to investigate before I start ordering parts.
Does the crank pulley have cracks in the rubber that is between the inner and outer metal parts? That rubber will fail. I replaced my pulley with an ATI.
I don't know yet. Looks like I'll need to get the car off the ground so I can remove the wheel and arch liner to inspect it. That will likely have to wait until later this week.
If anyone can help with any of this, please do, I'm trying to educate myself. Seems P1109 isn't a MINI code, you won't even find it on the Gen1 list in the M/A Library. It's a BMW code but it applies to the MINI so we ought to have a MINI-specific definition. Maybe we can fix that... I wonder whether slightly different applicability to different models in the BMW family would explain why I find slightly differing code definitions depending on where I look, and just a word or two can significantly change the focus. My latest find seems to point to the MAP sensor. TroubleCodes.net's list for the MINI defines P1109 as "Manifold absolute pressure (MAP) sensor – signal too high under deceleration". I don't know whether that's saying the MAP itself might be faulty or the MAP is the thing that's showing there's an issue. If the latter, at least this would narrow down the options but I'm not sure what I should be checking. Aargh, I hate these damn codes. They almost never tell you enough to point you at specific potential faults unless you already have experience with them. :mad2: This is one of those rare occasions when I actually wish the car was showing symptoms but it isn't. As far as I can tell, nothing has changed, it runs the same as it has for years. I think I'll try clearing the code and see what happens.....
The Bentley manual has: (p-codes) P1109 (MINI FC) 4361 Manifold Air Pressure Too High on Deceleration This is in the OBD code section. This picture is from the Diagnostics Tool and Techniques section. As you can see it says the "MAP signal too high during decel"
If I were a guessing man, and I am because its your money, I would say a TMAP sensor. Is it not running any different?
Welllllll.... See, there you go.... He has a R50..... No whirligig on his engine.... So that means he should look at his MAP not TMAP...
True. However, even the Bentley adds to the uncertainty. Look at that first scan. It says for the Cooper to go to MAP sensor on page 13-117 and for the Cooper S to the TMAP / MAP on 13-120. So, it's a Cooper so we go to the scan of 13-117 and all it shows is TMAP. Don't get me wrong, I know it's MAP only for the Cooper so this doesn't make me uncertain about that, this is just one of those rare times when I question the dependability of the Bentley when it seems to cross up references. Thanks, by the way, for reminding me about the Bentley. I have my own but it's not usually much help when I'm trying to diagnose and I didn't think to look there for the P1109 definition.
Okay, my version of the Bentley disagrees with MCS02's version! My Bentley says the R53 has both a TMAP and a MAP but the R50 only has a TMAP. WTFO?