So long story short, for the last 6 months I’ve had a P2096- Post Catalyst Fuel Trim System Too Lean Bank 1 CEL on in my 06’ R53. I’ve searched and searched but could not find the source of the problem. I recently came to the conclusion that I have a small pinhole leak somewhere in the system, and have given up searching and have just lived with the CEL, bad gas mileage, and loss of power Fast forward to last night: I get in my car, crank it up… no CEL. Drive around, still no light. Wake up this morning, no light. Not that I’m complaining but… Do our cars have the capability of adapting to a constant problem? I’m wondering if my ECU noticed that I’ve been running lean and adjusted the air/ fuel ratio to compensate for the loss of air. Any idea’s?
I had that SAME code for a long time due to a bad cat on a header I was sold. There has been a another header put on my car and I was told I would have to take my car to a professional to have them clear the code. I did not due to being busy with a family crisis. The SES light has gone away on my car as well, for at least 400 miles now. Who knows.......
So can anyone shed some light on this? I was told I would have to have a professional clear the Po296 code to get the code cleared and make the SES light go away. Neither I or that7guy ended up having to do that. Anyone?:idea:
If there is no fault after a certain amount of cycles the ECU resets and says turn the light off. There may still be a reading that the code was thrown at some point but since it's cycled through enough times without the fault there is no SES light for this issue.
The ECU does have short and long term fuel trims to keep the AFR stable if there are broadband VE changes [i.e. ported cylinder head, camshaft]. It will try to keep the engine running according to its tables within its ability to adapt. Regarding the light turning off after a while, Nathan is correct. After about 5 "clean cycles" of operation, the code will usually clear itself and turn off the CEL.
From the Bentley Manual: Conditions that illuminate the MIL (Malfunction Indicator Light)* - Engine management system fault detected for two consecutive OBD II Drive cycles. - Cat damaging fault - Malfunction in component(s) monitoring emissions - Manufacturer defined specs exceeded - Implausible sensor input signal - Misfire - Leak detected in fault tank evaporative system - Failure of DME to enter closed loop operation within specified time - Limp Home mode is entered In this case it is probably the first item - So what constitutes two consecutive OBD II Drive cycles. A drive cycle is considered complete when all of the diagnostic monitors have run their tests without interruption. For a drive cycle to be initiated, the vehicle must be started cold and brought up to 160F and at least 40F above it's original starting point. A fault code is stored upon the first occurrence of the fault being identified. Two complete consecutive drive cycles with the fault present illuminate the MIL. The exception is a cat damaging fault which turns the light on immediately. Once the MIL is illuminated, it remains illumiated unless the system is tested and found to be without faults for three consecutive drive cycles. In all cases except cat damaging faults the code is cleared from memory if the system is checked through 40 consecutive drive cycles without the fault being detected. For cat damaging faults it take 80 consecutive cycles. * We tend to call this the SES (Service Engine Soon) or CEL (Check Engine Light)
So to recap in simple form.... Code is tossed and is stored. Next drive cycle code is tossed again - CEL is lit Next drive cycle no code - 1st code is stored in memory, cleared if after 40 drive cycles code is not tossed again. Code is tossed in 2 consecutive cycles - CEL is lit until there are 3 consecutive cycles without code being tossed.
DOES YOOUR R53 HAVE A FACTORY EXHAUST STILL INSTALLED? IF SO, CHECK THE WELD AFTER THE FLANGE, RIGHT AFTER THE REAR O2 SENSOR. THAT WELD TENDS TO LEAK, SUCKING IN AIR AND CONFUSING THE O2 SENSOR. JUST A THOUGHT....
fasteddie: While your name is in lower case, YOUR POST IS IN CAPS. You should check your computer--I don't know if the website rules allow for YELLING an entire post. :blush2:
OK, we were on our way back from Ohio last night and over the course of the time out there I did have to use one tank of 92 octane instead of the usual 93. On our last stop for fuel before reaching home, we stopped at rest area shut car down, went in for a drink got back in, started back up and drove to pumps and shut down. Filled up, and surprisingly had the best mpg of the trip. Started the MINI and the ses came on. MINI ran great the whole way cruising between 80 - 90 the whole way home. Put the scanner on this morning and got what seems to be the dreaded P2096. Read a whole bunch of stuff about possible causes, went outside cleared the code, started and stopped MINi several times, rescanned, no codes but readiness test not completed. Took MINI for a ride, rescanned and now it's a pending code only. Going out to check for exhaust leak at cat to cat-back, as the rear section had been removed when I installed the B&M SS last year. The only thing different in driving had been while out in Ohio, we ran autocross on a really tight course and never got out of first gear and it's been about a year since a 12 hour high speed road trip. Going out to check some things now, any new data on this code would be appreciated. Cheers Mr. Jim
Last night I replaced the gasket and tightened the lines to the occ, cleared the code ran the car, rechecked, no pending code either, drove to fill up and still no sea or pending. This morning on the way to work the ses came on! I also put a bottle of techtron(sp). Will check ses later tonight.
Same code again! Have 4 days left on the 4 year so I dropped it off at MINI of Morristown today and they'll check it out on Monday. They also mentioned that the o2 sensors are now covered up to 100,000 miles if it throws the ses light. Anyone heard this ?
Well finally got RDNZL back last night , it was traced to a small pinch/hole in the intercooler boot. Once the boots were replaced and adaptive values reset she's all good again.