anyone in los angeles know of somewhere to get your car "passed" for smog? im about to pull my hair out dealing with this. ive been trying for almost 2 years to get my cat to reset and it just won't! i had some stereo work done to replace blown speakers and a new head unit put in. and from disconnecting the battery i think that triggers the cat to have to be reset again. so ive tried every driving trick in the book thats supposed to reset it, but nothing works. we've also changed everything possible and the f(&(*& thing will not reset. it doesn't throw codes and everything is perfect so im lost here. im ready to submit and just pay someone off to get this done. any help would be appreciated. thanks fellas!

 

I've never heard of having a cat reset. If you're not getting any codes then how are you failing smog? If it's an actual emissions problem out the tailpipe then your downstream O2 sensors should be detected a failed cat and this should trigger a code. Have you monitored the output to see what the voltages are? Fronts too for that matter. You can do this for about $20 with a smartphone and it might give you some insight to where the problem lies. Or swing by the auto parts store and see if they'll do it for you. Failing an emissions test is typically the result of a failed cat not burning off enough of the exhaust gas, or failed sensors not telling the ECU how to dial in the fuel injection system for a clean burn. Anything beyond that means more severe engine problems than a fully funcitonal emissions system isn't able to compensate for.

 

The ECU has a catalytic convertor test to make sure it has gone through it's heat cycle and is working properly. You won't be able to pass smog if this is not the case. Generally (from what I've read regarding other vehicles) you need to warm the vehicle up and drive about 5+ miles at 45mph to get it to go through it's cycle. I had to do about 15 miles of back roads driving to get mine to pass the self test. I recommend the Bluedriver OBDII scanner as it has a smog check function that tells you if the cat and other various emissions components have gone through their testing phases yet and are ready. Unfortunately this code reader does not support enhanced functions like ABS/SRS for the Land Rovers. I had to buy another one for those functions. The Bluedriver is available on Amazon and is $100. Disconnecting the battery or clearing any codes will reset this whole process, FYI. Also, for ease of passing, find a smog station that DOES NOT have a AWD dyno so they can only do the visual inspection and OBDII tests and not hook you up to a sniffer. Best of luck.

 

And how does the ECU "learn" that the cat has gone through its heat cycle? Through the downstream O2 sensors? They don't measure heat, only oxygen content.

 

There are four O2 sensors...One before each cat, and one after. That is how the ECU can determine if the catalytic converter is working correctly (e.g: it is up to operating temperature and working correctly - or there is a malfunctioning and blown out cat - basically the ECU has to determine that the cat is working correctly and not blown out for a certain time period at a certain speed and load...that's the "heat cycle" or "readiness cycle"- making sure its heated up to operating temperature and working correctly, cold cats don't do anything)...The O2 sensors also have a heat cycle ("readiness cycle" - the O2 sensors are heated to bring them up to operating temperature so that they read correctly - at least that's how it works on many vehicles and the Disco 2 O2 sensors are labeled as heated, so I would assume it does this as well - there is a readiness cycle for O2 sensors in the ECU).....Read this thread for the official drive cycles...

2000 Discovery ii Drive Cycle info needed - General Discussion Forum - NCLR - Northern California Land Rover Club

I believe "Drive cycle D" is the one for the catalytic converter.
Again, if you have the proper OBDII scan tool that can read the readiness tests it will tell you what ones are applicable to the vehicle and whether it has passed them yet...

 

Right, so how does the ECU determine this if the downstream O2 sensors have failed? And how is the cat reset? That's the part I'm confused about. Either the O2 sensors have failed or the cat has failed. Or the engine is so badly out of whack that the emissions system can't compensate. There's no resetting of the cat that will overcome any of this.

 

If the rear O2 sensors have failed the ECU will issue a code for as much and the readiness test would be a separate issue as far as smog goes. No no, the cat doesn't get "reset." It's just a test to make sure that the cat is working correctly by the ECU analyzing the readings from the upstream vs the downstream O2 sensors. THERE IS A CAT READINESS TEST!!! lol. If the vehicle has had the battery disconnected and the memory in the ECU is wiped, or the code's are cleared and the memory wiped, the ECU has readiness tests that it needs to perform before it will pass smog - this is for ANY OBDII vehicle. As far as I am aware, all OBDII vehicles with upstream/downstream O2 sensors performs this check as part of the requirements of the OBDII system/protocol. I'm not a professional mechanic, all I know is that every OBDII vehicle I have ever owned or seen is this way. Not all of them have the same readiness tests, because not all of them have the same equipment though - like not all vehicles have EGR or SAI, but they all have cats and O2 sensors. Again, the original poster NEEDS to get a OBDII code reader that can read the readiness tests so he doesn't just waste his time and money trying to get it to pass smog, whether that be a Bluedriver (if you have any GM or Japanese vehicles this is DEFINITELY the one to get IMHO).

I am in California just like the original poster, if the smog shop does not have an AWD dyno all that they do is do the visual inspection, hook up the OBDII and check for codes and that the readiness tests have been passed (e.g: you didn't just wipe the ECU before you went to the smog shop to clear any codes)...

 

thanks guys for all the input and this is seriously baffling. ive changed out literally everything having to do with the cats other than the cats themselves including reflashing then replacing the ecu altogether and every sensor there is and then some. like you guys all said once you disconnect the battery it triggers the system to start over and regular driving cycles reset everything. not sure if my wording is correct exactly, but hopefully you get what i mean as ive been dealing with this for 2 years seriously. ive had it at a land rover specialist and taken it to the actual dealer. it never throws any codes but going through and checking the computer it just keeps saying "cat" not ready! the guys at the dealer didnt know what to do because they said there are no codes so they can't really check anything unless there are. the land rover guy ive taken it to about 2 dozen times is like ive done everything i can do, he doesn't know what else to do. other than replace the cats, but he's like they're not flashing a code so don't spend the money, not to mention finding them. so any ideas keep em coming please

and btw im not continually going to the smog shop failing time after time for anyone who was wondering. i have my own scanner and the guy at the rover shop has a professional unit and all it keeps saying is CAT not ready. basically we've gone one item at a time then i do a drive cycle and go back and same thing CAT not ready. and to be clear ive done about 10 different versions of drive cycles that every expert and not expert alike has recommended! same **** with every possible thing on the car that could be related for 2 years! its in flawless mechanical condition and only has 50k miles on it also.

this happened the previous smog check to me like you guys have said. it failed so i drove it out on the highway about 20 miles out and back then i passed just fine. so not sure what the f*^& is going on here. but its been a nightmare.

 

Bad ECU

 

Just re-register your disco as a "tractor"