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The garage queen was due for smog last month and like a dumbass, I reset my ECU b/c it had two P codes (throttle related...I have a Sprint Booster that unplugged itself and I thought these might fail me at smog). And, shocker, now I am unable to get the CAT monitor to reset.
So off on a few drive cycles I went, never really able to drive it exactly as prescribed (idle on cold eng w/ 1/2 to 3/4 fuel for 2:15, 20-30 for 3:00, then 50-60 for 15 min followed by 5 min idle). I would love to hear where folks get this done in San Diego County. Doing 55 on the fwy at 0400 is trolling for either drunks or black and whites. I nearly got rear ended this morning trying to do the reset eastbound from SDSU area. I'd pay more though for the name and address of the engineer from CARB who mandated this insane requirement as I fought O2 sensor reset on an E46 M3 whose battery died and necessitated a drive cycle. Fought that one for months and finally threw new O2 sensors at it which resolved the monitor status.
I've installed O2 bung extenders trying to 'coach' the downstream sensors into compliance but no joy. My GT3 has 128k miles and hasn't given me a lick of drama over the past 3.5 years until now and I'm ready to leave the keys in it parked downtown as I am unable to get the Catalyst Complete. I read in one thread that this particular test needs the 50-60 mph part of the test the most but it could be bad word of mouth. Why/how nobody has cracked the code on drive cycle engineering astounds me and 'hard resets' via PCM will alter your CHK SUM value come time to smog and CARB has started breaking ***** over cars with non-OEM CHK SUM values (key victims being CARB legal superchargers on early 2000 Mustangs that have a tune for the supercharger and CARB's response is, "Oh well. The number of affected folks is small"...which means your Procharger WITH A CARB EO STICKER has to come off and get flashed back to stock....CARB can KMA).
I've attached a screenshot of two O2 graphs from data retrieved via WiFi dongle in the OBD port and OBD Fusion app on the iPhone. Notable features:
1. Speed trace is black and one file is near the end of the drive cycle where I did 55 and then idled at rest for 5 min while the other is cruising at 73 mph on the RTB from Dehesa.
2. Upstream O2 values are charted in red/yellow.
3. Downstream O2 values are 2 shades of blue.
4. Horiz axis is in seconds and Vert axis is O2 voltage (btwn 0 and 1)
Curious if anybody sees a 'lazy' sensor or inference of weak cats. There should be P codes for each but I have none. Also eager to hear where folks go to get this drive cycle complete...another PITA feature of living in San Dawg
Actually, since you live in San Diego, you are golden.
Speak with Adam Gill @ Vollig.in Miramar area.
He has extensive experience in getting 996 / 997 GT3 to complete the readiness cycle dance.
ps, if you exceed 59 mph and 2999 rpm, you will fail the drive cycle.
72 mph = no go.
Drive cycle procedure attached.
Yep- I know the 72mph graph was a non-starter for the test purposes and just threw it in there FWIW. So many questions WRT the test such as does the testing 'accumulate' time in zone? Does a 10 min pass at 55 mph followed by a 5 min pass on a subsequent drive count for 15 min or will the bit flip not occur unless test is run in its entirety?
Ordered 4 new O2 sensors and will pop the rear bumper off and get 'er done and hopefully put this one to bed b/f I lose the gamble on trolling for drunks or chippies.
Yep- I know the 72mph graph was a non-starter for the test purposes and just threw it in there FWIW. So many questions WRT the test such as does the testing 'accumulate' time in zone? Does a 10 min pass at 55 mph followed by a 5 min pass on a subsequent drive count for 15 min or will the bit flip not occur unless test is run in its entirety?
No. you need to do separate unique tests to have hopes of setting the cat readiness monitor.
Ordered 4 new O2 sensors and will pop the rear bumper off and get 'er done and hopefully put this one to bed b/f I lose the gamble on trolling for drunks or chippies.
Buying 4 new O2 monitors sounds like you are just spending $$ hoping it resolves the issue.
that's cool, it's your $$
A simple durametric O2 sensor test will quickly show if sensors are bad.
Several threads on just this subject are in this forum.
Buying 4 new O2 monitors sounds like you are just spending $$ hoping it resolves the issue.
that's cool, it's your $$
A simple durametric O2 sensor test will quickly show if sensors are bad.
Several threads on just this subject are in this forum.
I dove into the O2 sensor threads and I believe this one is good for at least 2 college credits. Excellent detail but I have yet to read any objective data references that can identify a 'slow' sensor. Sans P code error, can Durametric identify a lazy or slow sensor?
Given all the recommendations regarding life expectancy on the sensors, I feel good about swapping them out for new ones. One side note- my mpg was 13-18 mpg and to be honest I've never given a damn about the fuel economy but this strikes me as low. Hope to get the Bosch sensors in by end of week so we'll see. Appreciate all the help here.
Installed the new O2 sensors and went for a quick data capture drive. Attached image compared the new downstream sensor's voltages against the old ones (new downstream are red/yellow, old downstream are blues). While I can't objectively quantify the specifics of a 'lazy sensor', it appears that the new ones are well aligned on the 50 mph profile run. I'll wait until oh dark thirty and go trolling for drunks again (did I say how much I hate this drive cycle BS?) to see if I can trip the cat ready. Given the marked performance delta btwn the old and new, I'm feeling good about this one. And if I'm wrong, there will be a black GT3 with the keys in it at the In & Out in El Cajon.
old (blues) vs new (red/yellow) downstream O2 sensors at 50 mph and idle (black line)
I just went through it as I relocated here and to cgfen's point I had Adam at Vollig set the flag for me, 3 times in the last few months.
It costs you an hour of labor or $139 if I recall to get the flag triggered.
Apparently it is so sensitive he sits in the car with his laptop and has to be 100 RPM accurate to actually trigger it so there is no way you can get there on a drive cycle.
I have driven 100s of miles and could not set it not mentioning as you said how dangerous it is in regular traffic.
Does Adam do it on a Dyno? I've also heard that 'hard flipping' readiness codes will change the ECU total line code chk sum and while I don't know if CARB has yet got around to 996 GT3's factory chk sum data, I do know of a number of folks who had to remove CARB legal superchargers on 03-05 Mustangs due to the fact that the chk sum value didn't match OEM value (and the CARB district supervisor's paraphrased response was, "Well, not that many have superchargers with an EO # so because its such a small number, we're not going to waive the chk sum requirement" so the Pony owners had to pay to have their their superchargers pulled/ECU flashed to stock in order to pass smog. ****ty deal to say the least).
Bottom line up front: No joy today on CAT ready flag reset.
I did a run up Laguna this morning. I thought that would be my best shot at keeping it at 50 mph for at least 15 miles. I have heard that 'large throttle inputs' will kill the test, but what nobody has quantified is how much throttle delta/position is acceptable. There are so many damned subjective pieces of advice that leads all of us to fly blind while trying to reset a readiness indicator. We know which portions of the drive cycle test which component, but there's no data on which components can be set doing that portion or if the whole drive cycle must be performed (which can't be the case because nobody performs the drive cycle portions getting in the car to go to work and certainly when they [we] have a seriously difficult time keeping it under 3k rpm thus the computer must accumulate the values it is looking for in order to set the ready flag).
There are two different sources that say the cat resets on the 50-60mph cycle for 15 min (with one rennlister emphatically stating it must be 55 mph period dot), but there's also a drive cycle that uses 40-60 so I tried 50 on cruise control heading up Mt Laguna to balance my probability of getting stuck behind someone or going too fast by the hikers that park on the other side of the cattle guard where everybody takes their kids when its snowing.
The graph shows 16 min of 50mph. Notable data points:
-Throttle range was low of 4 and high of 16%
-The difference between the 2 downstream sensor values averaged .1
-RPM never exceeded 3k
-Car was restarted at the base of Laguna
I pulled over and idled for 5 min and restarted with the intent of performing another test on the downhill portion to see if throttle position would make the difference but while I was idling, 3 European enthusiasts went by me and I couldn't help myself so off I went to exercise the horses. The best part of the day was a WOT deep 3 digit velocity verification that my newly attached Demon Speed splitter would keep the nose planted. It performed like a champ and made the car much more manageable at speed. With the RS tail and no splitter, it was quite sporty...
So I'm going on a dawn patrol tomm to do 55 mph on the fwy for 15 min. If that won't do it, I'll call Adam next week...but damn, I hate tapping out!
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Well, on the bright side, at least you have had a good excuse to get your car out and drive those great San Diego roads!. We have a place in Mission Beach but I have yet to get my Gt3 down there LOL.
I tried to do it myself as well and logged over 1,500 miles with no luck of ever triggering the cat readiness flag and my car is completely stock. 2 years ago when it was due for SMOG and the car was new to me I had it done at the dealer in the bay area where I lived. For this renewal since I moved to SD I went to Adam. I actually had to have him do it twice as I was running into an other issue that triggered error codes.
He does not have a dyno so I don't think that is how he operates. I did ask him what I was doing wrong in the drive cycle and his answer was that on the 996 GT3 it is so finicky you basically cannot trigger it blind that way. He said he is in the car with his laptop and he has to feed RPMs within a precision of 100 rev in order for the flag to get set.
He has other customers (mostly with speed yellows) who come to him basically every 2 years to set that flag. He just charges one hour of labor which I think is $139, the dealer charged me $400 or so at the time. I hate the SMOG process, but if I were you I would go to Adam, feel free to let him know Renaud with the speed yellow sent you. He is a good guy but super busy.
Good luck, hope you can get it sorted soon!!! I had to drive for over 6 months with expired tags and it is just unnecessary stress.
I went through the same drama last year. Do not waste your time, do not throw parts at it hoping it will do it, just go to the guy who knows a guy. As above Rennlist'er has suggested.
@Renaud Bizet who did you use set the readiness flags in the Bay Area? I disconnected my battery for some interior work, and will need to get the readiness monitors set in the next 6 months or “move” to a county in CA that doesn’t do biannual smogs.
I had "Cat not ready" several years ago. Did multiple drive cycles (Dublin to Paterson & back) with no luck. Finally took it to Kahlers. $3000 later (new cat, oxy sensor and shop time) and passed smog. Have passed two subsequent smogs with no issues.
Wish the smog sheet showed the numbers instead of just "passed". Can't tell how well its doing to contribute to the Republic of CA fight against pollution.
01-08-2022, 04:05 PM
Another Dreaded OBD Drive Cycle PITA
