crwarren11

I had a similar problem not too long ago with the same codes. In my case it was a leak in the intake tube between the MAF and the throttle body. I used a smoke tester to locate the leak, repaired, and it has not come back. In the past I have dealt with these simultaneous codes and they have also been leaks in the intake (rubber boots cracked and/or torn between the plenum, loose connections of the same, cracked hose from the AOS). As others have said there are several root causes which you should not ignore but from a relatively easy first step I would look for sources of unmetered air getting into the intake after the MAF. If it is bad enough to cause a stall then it might be obvious…this usually happens to me when I forget to put something back together after some work that required removal of the intake and/or plenum.

Some good news to report. Monitor went ready yesterday and passed smog. I know I’ll still need to deal with that cat at some point but I’ve got a couple of years now to look for a replacement.

No check engine light or codes?

Agreed. I have a few more things to try before succumbing to new or used cats but definitely on the radar.

Ahh likely the case here in CA. I know theft of cats are a big problem here. There are zero listings on Craigslist. Interesting that the entire x-pipe including cats are really easy to find for my M3.

This is probably why I didn’t see many on a quick search. I’ll get into it more as I have time to really dig.

Yep I am hoping to find some lightly used cats. I did a couple of quick searches without much luck but didn’t put a lot of time into it yet.

Thanks for the help guys. I suspect bank 2 cat is bad. I just wish that it was good enough to give me a ready state to pass smog. Not quite ready to give up hope but getting there.

Thanks. It is still confusing me why, if the cat is bad, that I am not getting the associated code. Just that the monitor is not ready.

I typically use Durametric to read the values, but happened to have a wireless reader plugged in today so I can show you the readings. As you will see, Bank 1 looks good, O2 sensor after cat is steady (green line). Bank 2 O2 sensor after cat (green line) is oscillating, not as much as pre-cat (red line), but certainly less than ideal.

Ok, finally smoke tested and had a couple of findings. The intake tube had a leak at the location circled in red. I repaired it with RTV silicone. Two locations on the intake manifold, also circled in red. I saw another post about someone having a leak at the place where the internal flap is located, so I'll look into that. On the SAI hose, I noticed that it does not have the bulge at the end of it like the other one. Wondering if this is the cause of that leak? All back together and everything is running great. No CEL and no codes stored at all. All monitors are ready...except for the catalyst once again. I will continue to drive and hope that it is just needing more drive cycles, but the voltage of the O2 sensor behind the cat on bank 2 is still not great, but maybe good enough to pass? Not sure. I would love to hear if anyone thinks this less-than-ideal voltage on the O2 sensor is what is causing the monitor to not be ready, even without any of the typical codes for cats going bad.

Quick update...I put in the new O2 sensor behind the cat. The old one had a fair amount of fluid on it. It seemed like oil to me but not 100% sure. Also, I noticed that the O2 sensor ahead of the cat was quite loose - probably two full turns out of the threaded hole, so I tightened that one down. On the intake side, I removed the air filter, MAF, large intake tube, and throttle body. As someone else had mentioned, I found some debris and a fairly large leaf on the screen ahead of the MAF. I vacuumed all of that out of the filter area and intake tube. I cleaned up the throttle body, but it didn't seem too dirty to me. I put everything back together and then tried the smoke tester. I never got any indication of smoke coming from the intake system, even after ~10-15min of smoke going in. That said, I am questioning the location where I was putting in the smoke. I used the hole where the SAI hose goes into the right-side plenum. Sorry, first-time smoke testing here...is this a suitable location or is somewhere else better? I have not had the chance to run the car yet other than pulling into the garage. Hoping to get some more time to smoke test this week.

Hi all, Looking for some guidance here on a 2000 Boxster Tiptronic with about 120k mi. I am intermittently getting P1128 (360) / P1130 (361) codes which will sometimes cause a CEL and also sometimes the CEL will also go away without resetting. Durametric specifies these as idle range codes. I know the typical reasons for these codes which I am chasing down right now. I have a smoke tester being delivered tomorrow to investigate further if there are any vacuum leaks in the intake. For context, I replaced the MAF about 6 months ago as I thought this could be the source. I did the oil cap test and idle changed when I took cap off, so that leads me to believe it is not crankcase vacuum leak. No smoke on startup and the AOS is relatively new (5ys, 10k mi on it). Put in a new fuel pump 4yrs ago (8k mi on it). SAI system does not appear to be an issue based on lack of codes and SAI readiness being good. I tightened the clamps around the intake boots last weekend thinking this could be the problem, but got the CEL again this week. I will check the air filter and throttle body this weekend for debris when I do the smoke test. Getting around to my question...I went to get smog check (California) when I had no CEL for quite some time, and all readiness monitors were good except for Catalyst. Before the CEL came on this week, I checked readiness monitors and again all were good except for catalyst. Are there any possible correlations between these codes and the catalyst not being ready? Does this lead you to suggest any other things that I should check? I have checked the O2 sensor voltages for all sensors. All look good except for possibly Bank 2 behind the cat...it basically follows the O2 sensor ahead of the cat. I ordered a new O2 sensor and will replace that this weekend to see if it helps. I am fearing that maybe that catalytic converter has gone bad due to the signal I am seeing, but I am not getting any specific catalytic converter codes and have not over the past two years of seeing this. Fingers crossed it's just the O2 sensor, but I changed that one about 6yrs ago (only 16k mi on it since then). Maybe irrelevant but I also get the occasional P0197 code for oil temperature sensor below limit. Please let me know your thoughts. Thanks!

I am far from an expert but I had a fuel pump go out and the tell tale sign for me was the pressure at the fuel rails. Easy to check at the schraeder valve on the rails. I had also gone through the process at the crankcase sensor but that turned out to be fine. You might also check out this thread.

I would expect a mechanical problem in the transmission to issue a fault code. Bad solenoids or valve body, worn clutches, low oil, will all trip a fault code which will be seen in Durametric for sure. Wondering if it is the control module in the trunk? I have been told before that these can go bad and replacements are available through eBay for pretty cheap. Might be worth exploring? Someone here may also be able to offer you one to swap in temporarily to see if it resolves the problem.