Hello all,

I have a 2005 "justa" that "just" recently turned on the MIL light and I found a P2097 code with my reader. "Post catalyst fuel trim, system too rich." And I have two issues:

A) proper diagnosis of the root cause
B) an emotional blockage concerning connecting unknown software from Eastern Europe to my car

So, (A) - I've found and read this existing thread:

"SES, O2 Sensors, P2097"
https://www.northamericanmotoring.co...ors-p2097.html

among others.

And also referred to the trouble code section of my Bentley's manual.

And, frankly, I have yet to find a good, clear, complete description of exactly what should be tested to efficiently diagnose the source of the problem. Going straight to replacing sensors or clearing adaptation values seems a little cavalier.

So here's what I've read/learned so far. All corrections / additions that help compile a proper diagnosis procedure will be greatly apreciated:

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The code means that the post-catalytic converter 02 sensor says it is detecting too rich fuel.

This condition can, in theory, be caused by many things, such as:

a) a failing post-cat 02 sensor (they do have a lifespan)

b) possibly compounded by a failing pre-cat 02 sensor (according to Bentley: "the signal of the post-cat sensor is evaluated over the course of several pre-cat sensor oscillations..." - so I'm guessing that conceivably a failing pre-cat sensor could mess up the oscillation period used for measurement?

Bentley's says both sensors can be tested electrically so you don't have to do the expensive experiment of replace-and-see.

b) a failing catalytic converter - literally, the cat converter uses 02 to convert exhaust gasses. If it's not working, could mess up the post-cat fuel measurement. But Bentley's say the code for a failing cat is P0420.

c) Bentley's also says to check the fuel supply - but I have to admit I don't really follow. The main tests it suggests are pressure and volume - but honestly, what are the odds that there's a problem with the fuel pump the results in too much gas being delivered?

d) I found, buried in the "Diagnostic tools & techniques" - this gem - Exhaust back pressure testing. Says "Increased back pressure can cause multiple driveability complaints. Some examples are ... fuel trim faults (indicating rich misture)...

e) THEN - after whatever is the root cause of the code has been fixed - THEN it says to have the adaptation codes reset, 'cause they won't reset themselves. But this is suggested as step one in the thread referred to above - where someone suggests buying a $50 CD and cable from someone in Romania to do this myself. And the biggest proponent of that is a guy with a single post (who signed up just to share this great find??) In this day and age, I will admit some trepidation at doing so.

So - does this cover all the bases of what to test? Or is it 99% of the time "problem x" and just go straight to that? Or what?

Thanks to anyone with wisdom to share on this topic.

 

hmmm...did I post in the wrong area?

 

For the record - the issue resolved itself. After driving for a few weeks and ~ 500 milles, the MIL light just went off all by itself. I'll check and see if the cose is cleared.

 

Have seen issues with the 05's with respect to O2 sensors. So much so MINI has an extended warranty on them for 05/06 models. Maybe start there.

 

See Ive got the p2097 code and getting rather crappy fuel milage for what it should be. I have 2 theories myself.
Theory one is knowing how neglected the maintenance has been on my 2005 I suspect the o2 sensors may be toast or at least carboned up.. oil deposits too.. Theory two is maybe the intake ports are so gummed up and restricted it cannot get the air need to provide a proper air fuel mixture. I do plan on walnut media blasting.

 

Ive got the p2097 code and getting rather crappy fuel milage for what it should be. I have 2 theories myself.
Theory one is knowing how neglected the maintenance has been on my 2005 I suspect the o2 sensors may be toast or at least carboned up.. oil deposits too.. Theory two is maybe the intake ports are so gummed up and restricted it cannot get the air need to provide a proper air fuel mixture. I do plan on walnut media blasting.[/QUOTE]

Have you made any progress on this? I'm about to dig into the same code/problems. I clearly have one sensor that is in need of replacement.

 

Have you made any progress on this? I'm about to dig into the same code/problems. I clearly have one sensor that is in need of replacement.[/QUOTE]
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I have the same code on my 2004 (R50) and am not sure where to start. Any update on your situation?