Admins here do not allow advice on breaking laws, therefore for off-road use out of state; Yes you can set downstream O2's to "do not report" which will have them identify as installed/functional and not cause CEL code. If cat efficiency is poor, it may be getting clogged or start to chip out and rattle soon. That is why out of state off-road folks will gut out the insides.

 

I bought two bottles of Cataclean at AutoZone for $55 and used one already, the check engine light went off so it might pass inspection after the second bottle is used up and the GM driving cycle is run twice.

 

Why would you need the GM cycle to run twice if the Cataclean turned the engine light off? If the engine light is off you better go smog it while the gettin is good. Otherwise that light could come back before you get around to smoging it.

 

I wish I could do that but I don't think the car will pass inspection without performing at least one GM driving cycle because codes were cleared before the Cataclean was added. I've had GM cars fail inspection because codes were cleared and the driving cycle wasn't done.

 

Why’d you do that?? I thought you said the check engine light went off after you put the Cataclean in? So you’re saying the Cataclean didn’t do anything afterall?

 

The Cataclean did turn the code off but the driving cycle needs to be done to pass inspection, I just completed driving one cycle and the check engine light stayed off. For example, let's say a code comes up that turns on the check engine light and you use a scan tool to clear the code just before you have it inspected. The car won't pass inspection without doing at least one GM driving cycle because not all the readiness flags were reset, Does anybody do the GM Driving Cycle?. So far the Cataclean has kept the check engine light off.

 

Ok I think I understand what you mean, however lets forget the scan tool altogether. It’s irrelevant because it wasn’t even used, right?

So the way I’m understanding you is if a check engine light is on and happens to turn off for whatever reason [I’ve had a car that used to have an intermittent check engine light come on for a week or 2 then turn off for a week or 2] at the point where it turns off, the car has to go through a certain number of driving cycles in order to check all sensors pertaining, including the ones that were just cleared when the engine light turned itself off for whatever reason. Correct? No scan tool required because the code cleared on its own, but it still needs to run a certain number of cycles while still passing its sensor checks to confirm they remain clear. Then and only then will the computer signal all clear and ready for testing.

I’m pretty sure I understand it clearly now and admittedly that last part is something I hadn’t known until now, but it makes sense.

 

Hi Hiltonny, I first got error code for bank 1 lean code , and car ran like crap and got bad mileage. Replaced narrow band up stream O2 sensors, and error code be gone. Then got catalytic converter bad code, replaced the wide band downstream O2 sensors, code be gone. $75.00 a pop, $300.00 for all 4, labor free by Johnny.

After clearing any intermittent check engine light codes, you must drive a complete drive cycle to clear all of the look up tables in the caddy’s computer to pass emissions at the DEQ by driving approximately 100 miles. Try 125, cus I drove 100, and it still wasn’t fully reset.

So, from the internet, must be true, the narrow band upstream O2 sensors determine the fuel/air ratio, rich/lean. The downstream wide band O2 sensors subtract from the upstream O2 sensors to say, the catalytic converters are scrubbing the exhaust of pollutants, ie doing their job. If there are no lean codes (upstream O2 sensors), and both catalytic converters aren’t broken and rattling, replace the downstream O2 sensors. If you still get bad cat codes, one or both Cats are bad and any catalytic converter of same dimensions can be substituted in place. The cats are tucked way up inside lower body and can’t be wielded like on a truck out in the open. Must disconnect exhaust manifold from engine. Also, these 2008 cats are a passive device, no active components inside. They get hot from engine exhaust and start working real good when nice and hot. That’s why all owners manual tell you to drive right away for quick cat light off and clean air sooner, and not warm up your car like my Daddy used to pre-cat years.

Johnny

 

I changed all four O2 sensors last November but the car was off road for the winter and wasn't driven until now, O2 sensor replacement question. It turns out that the sensors didn't cause the 430 error code but at 70,000 miles it didn't hurt to change them, from what I've read they get weak after 50,000 miles. The Cataclean seems to be working so far.

 

I changed all four O2 sensors last November but the car was off road for the winter and wasn't driven until now, O2 sensor replacement question. It turns out that the sensors didn't cause the 430 error code but at 70,000 miles it didn't hurt to change them, from what I've read they get weak after 50,000 miles. The Cataclean seems to be working so far.

Can we get an update?

 

What he said. Scan tool will clear error code but not clear the look up table in computer for passing DEQ. Drive cycle with no new errors will clear table. Can clear intermittent codes by disconnecting negative battery cable for a few minutes but not look up table. Scan device not required.
Be really sure the upstream/downstream sensors are the correct part numbers and in the correct places on the exhaust system.
Makes sense if problem is intermittent the check engine light might go away on its own after drive cycle. Broken wire or sensor then it would never clear. It pisses me off when I get a check engine light, so I try to fix, clear, and drive.
The cats are passive devices, no communication or control wires connected. The only way to get a bad cat code is the readings between the upstream/downstream O2 sensors.
Anyway, that’s what I read on the internet…
Johnny

 

What happens if someone does a proper repair but doesn’t clear any codes via scanner or by disconnecting the battery cables. Lets say he doesn’t give a damn about no damn codes. What happens to the car?

What he said. Scan tool will clear error code but not clear the look up table in computer for passing DEQ. Drive cycle with no new errors will clear table. Can clear intermittent codes by disconnecting negative battery cable for a few minutes but not look up table.

Technically, isn’t it the other way around? Scan tool will clear the code and also clear the the look up table, rendering it insufficient with not enough info to communicate with. The look up table requires at least a couple of drive cycles in order to gather enough of the proper information from the vehicles sensors. Or am I wrong?

 

I tried to find a thread - think it was from Team ZR1, .....IIRC the sensors readings/locations are misleading? something about front to back or left to right being counterintuitive?

 

In NY state you are allowed one system to be "not ready" and still pass inspection as long as the CEL is not illuminated.

 

On my 2008 STS-V, OBD 2 code 430 says that I need a new converter assembly for bank #2 but they have been discontinued and the dealer is unable to find a factory one. The dealer parts guy said that installing an aftermarket version would trigger a check engine light because the downstream O2 sensor is looking for the original converter treated exhaust.

I think the dealer parts guy is full of it. An O2 sensor is not a smart sensor - it's just measuring the amount of O2 in the exhaust stream. It doesn't have any way to "know" or sense what type of catalytic converter is upstream of it, or magically sniff the special NY/CA/CO exhaust gases.

 

I ran several GM driving cycles but it didn't pass inspection because some systems weren't ready, while doing another driving cycle the check engine light came on. A tip from a parts guy was to add a spark plug antifouler to the O2 sensor to move it away from the exhaust flow which was done and more GM driving cycles were driven. I have to connect the Tech 2 scanner clone to the car tomorrow to see if all the systems are ready for inspection or more driving is needed. Youtube has videos on the antifouler fix and an inline O2 sensor cable resistor/ capacitor filter fix. It would cost about $100 to buy two HP Tuner credits to tune out the downstream O2 sensors as a last resort.

 

Dang that sucks. Smog inspections can be among the biggest drawbacks when it comes to owning older Cadillacs, I’ve been through it many times in the past, it’s even killed a couple of mine. Sometimes the best solution is to just grease a few palms. Lol.

 

After the converter code was fixed with spark plug anti-foulers a lean code (P0174) came up for bank 2, it went away after the five year old Iridium spark plugs were changed. The car was inspected two weeks ago and everything was OK but didn't pass because all the monitors weren't ready so it was driven more and a cheap code reader was bought. The white inspection rejection paper was folded and placed next to the registration sticker, no one pulled me over in all that time so they must know about having to drive the car for the monitors since this years inspection sticker color is red.

Today the car passed inspection since the monitors were ready, one monitor can be not ready and the car will pass inspection so the difficult EVAP monitor might not have been ready but the converter monitor was ready.

If you have code 430 (bank 2 driver's side) or 420 (bank 1 passenger's side) first try the $10 18 MM spark plug anti-fouler fix as seen on various YouTube videos, Dorman part #42009. Both parts in this kit are used for the downstream O2 sensor, one has to have the opening drilled wider so the O2 sensor can screw into it then that's screwed into the other part and all three screw into the exhaust fitting which moves the O2 sensor away from the exhaust flow. It took a while for the converter monitor to finally become ready and having a cheap code reader that shows monitor status helps to know when it can be taken in for inspection or the need to drive more.

As far as replacing the catalytic converter in New York, I don't think it's possible because the California Carb versions are no longer available from GM and the aftermarket only shows one for the V6. I don't think that the aftermarket Magnaflow converters that fit the STS-V are sold in this state because neither version is California Carb compliant.

 

Bam!