2002 Jeep Wrangler 2.5L SE
I am simply posting this thread because I have been through the ringer with the CAT monitor, and I've read just about every thread on this forum and other Jeep forums regarding the idea of not being able to get the CAT monitor to reset after either 1) clearing monitors/codes with a OBDII scanner, or 2) disconnecting the battery.
To preface this post, I live in California, which alone has it's fair share of absurdities. However, what sucks about smog here is that you are unable to smog if the CAT monitor has not flipped yet; you can have any other monitor (just one) unready, but the CAT monitor MUST have cycled. And as we can see in a lot of these threads, it's a PITA! There should be a rhyme or reason to flip the monitor (i.e. Chrysler Drive Cycle), but after all the information I've seen, including my own experience, my only advice is to steadfast and try to make it flip the monitor per the Chrysler Drive Cycle, even though it seems to just "flip" whenever.
I always seem to find myself having issues with flipping the monitor whenever I need to smog; something happens right around the time for registration and of course, the CAT hasn't flipped yet. The last time I had issues with the CAT monitor, it ended up being an exhaust leak with the exhaust manifold itself; damn those manifold cracks! Once I replaced the manifold (two or three times, because the aftermarket replacements are all out of whack as far as fitment and don't seal properly; flanges too thick), I performed the drive cycle and she flipped immediately! Great news!
This time however was a little different. Had to do a head gasket replacement, and had some loud engine noise after the fact, so I tried my luck at removing the downpipe of my exhaust so I could drop the oil pan and check for anything being afoot. Of course, snapped one of the studs on the flange connecting the CAT to the downpipe, so I did anything and everything I could to remove that stud; heat, penetrating oil, BFH and finally it popped out. However, in the wake of all of that, I created an exhaust rattle after everything was back together and after I figured out the massive amounts of engine chatter (please, save yourself time and check the damn timing chain, ha). Because of the BFH, I thought the vibrations had broke loose the interior of the CAT, as that's where the rattle seemed to be coming from and why the CAT monitor wouldn't flip. It could also have been the muffler however, as the tailpipe started shooting fiberglass like crazy upon start-up.
Well surprise surprise! I'm almost positive the rattle is the muffler itself, as the CAT monitor has magically flipped today! Prior to the flip, I decided to hit Fiesta Island in San Diego today because it's raining, and it's fun to hit some muddy puddles for a change in an otherwise temperate climate. After 3 or 4 failed flips after completing the CAT specific drive cycle, I tried the same ol' cycle today and she finally popped.
I am unsure as to why it was delayed this time around. The last time I needed to flip the CAT monitor, it flipped on the first attempt right after battery hook-up, so the ideas looming in the ether of needing x amount of cold-starts before it flips is most certainly not true; again, personal experience. I was prepared to start testing the downstream sensor before ripping the exhaust manifold off to check for cracks (plenty of experience with the exhaust manifold and it's just a hassle), but somehow, some way, I lucked out on time. Again, no rhyme or reason it seems, as I read one post on here saying he flipped his CAT monitor cruising at 55mph on the highway at 3,000rpm which is not within spec of the drive cycle!
Moral of the story, be weary at throwing money at the elusive CAT monitor problem. Try to check all other factors first before dropping serious coin on a new catalytic converter, O2 sensor, exhaust manifold, etc. If everything checks out, give her some time to get situated and keep trying that cycle. I'd say all in all, it was about 1 - 2 weeks of driving, during of which I used my OBDII scanner to erase my intrusive P0551 code (this has been pending the entire time even after replacing the PS Switch and was still pending during the flip), and accidentally resetting the EVAP, O2, O2 Heater, and one other monitor, so really not that much time. On the 5th attempt at the cycle, while having fun in the mud puddles mind you, I checked the ol' scanner just for shits 'n gigs, and sure enough, she flipped. Not sure why now, but I know the CAT monitor is an annoying thing to rack your brain around, so here is my experience and I hope it helps whomever else out in diagnosing what's going on with their rig.
Cheers!
I am simply posting this thread because I have been through the ringer with the CAT monitor, and I've read just about every thread on this forum and other Jeep forums regarding the idea of not being able to get the CAT monitor to reset after either 1) clearing monitors/codes with a OBDII scanner, or 2) disconnecting the battery.
To preface this post, I live in California, which alone has it's fair share of absurdities. However, what sucks about smog here is that you are unable to smog if the CAT monitor has not flipped yet; you can have any other monitor (just one) unready, but the CAT monitor MUST have cycled. And as we can see in a lot of these threads, it's a PITA! There should be a rhyme or reason to flip the monitor (i.e. Chrysler Drive Cycle), but after all the information I've seen, including my own experience, my only advice is to steadfast and try to make it flip the monitor per the Chrysler Drive Cycle, even though it seems to just "flip" whenever.
I always seem to find myself having issues with flipping the monitor whenever I need to smog; something happens right around the time for registration and of course, the CAT hasn't flipped yet. The last time I had issues with the CAT monitor, it ended up being an exhaust leak with the exhaust manifold itself; damn those manifold cracks! Once I replaced the manifold (two or three times, because the aftermarket replacements are all out of whack as far as fitment and don't seal properly; flanges too thick), I performed the drive cycle and she flipped immediately! Great news!
This time however was a little different. Had to do a head gasket replacement, and had some loud engine noise after the fact, so I tried my luck at removing the downpipe of my exhaust so I could drop the oil pan and check for anything being afoot. Of course, snapped one of the studs on the flange connecting the CAT to the downpipe, so I did anything and everything I could to remove that stud; heat, penetrating oil, BFH and finally it popped out. However, in the wake of all of that, I created an exhaust rattle after everything was back together and after I figured out the massive amounts of engine chatter (please, save yourself time and check the damn timing chain, ha). Because of the BFH, I thought the vibrations had broke loose the interior of the CAT, as that's where the rattle seemed to be coming from and why the CAT monitor wouldn't flip. It could also have been the muffler however, as the tailpipe started shooting fiberglass like crazy upon start-up.
Well surprise surprise! I'm almost positive the rattle is the muffler itself, as the CAT monitor has magically flipped today! Prior to the flip, I decided to hit Fiesta Island in San Diego today because it's raining, and it's fun to hit some muddy puddles for a change in an otherwise temperate climate. After 3 or 4 failed flips after completing the CAT specific drive cycle, I tried the same ol' cycle today and she finally popped.
I am unsure as to why it was delayed this time around. The last time I needed to flip the CAT monitor, it flipped on the first attempt right after battery hook-up, so the ideas looming in the ether of needing x amount of cold-starts before it flips is most certainly not true; again, personal experience. I was prepared to start testing the downstream sensor before ripping the exhaust manifold off to check for cracks (plenty of experience with the exhaust manifold and it's just a hassle), but somehow, some way, I lucked out on time. Again, no rhyme or reason it seems, as I read one post on here saying he flipped his CAT monitor cruising at 55mph on the highway at 3,000rpm which is not within spec of the drive cycle!
Moral of the story, be weary at throwing money at the elusive CAT monitor problem. Try to check all other factors first before dropping serious coin on a new catalytic converter, O2 sensor, exhaust manifold, etc. If everything checks out, give her some time to get situated and keep trying that cycle. I'd say all in all, it was about 1 - 2 weeks of driving, during of which I used my OBDII scanner to erase my intrusive P0551 code (this has been pending the entire time even after replacing the PS Switch and was still pending during the flip), and accidentally resetting the EVAP, O2, O2 Heater, and one other monitor, so really not that much time. On the 5th attempt at the cycle, while having fun in the mud puddles mind you, I checked the ol' scanner just for shits 'n gigs, and sure enough, she flipped. Not sure why now, but I know the CAT monitor is an annoying thing to rack your brain around, so here is my experience and I hope it helps whomever else out in diagnosing what's going on with their rig.
Cheers!
