My '01 Maxima GLE has 116k miles, and Emissions time is back. My Check engine light is on so i take it to a Meineke that I have used before for emissions and service. They tell me that all three cat converters are cooked and aren't heating up at all. On top of that, all 4 O2 sensors are no longer functioning. They still haven't gotten back to me on a quote to fix everything, but I know that through them it will be upwards of $4k. A friend of mine knows cars much better than me and says that I could probably get away with swapping a few O2 sensors. He took me by an emissions place his friend owns and I got the error codes P0135 and P0430. The P0135 specifies just one sensor and the P0430 is just one cat conv. Here are my questions. Do I have to use Nissan O2 sensors or can I just use universal stuff, (there is a huge price difference)? What do you recommend in trying to fix this problem? My friend is a good mechanic but doesn't have a lift to get under the car to replace the cat conv's, but can replace the O2s if I get them. I had to replace 2 of the converters 2 years ago and it was a huge pain because 2 aftermarket converters wouldn't pass emissions and eventually we had to settle on Nissan made parts.
The car is probably only worth 6k on a good day, let me know what I should do.
Brady
Car Troubles...
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MinisterofDOOM
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Re: Car Troubles... (bradzzo)
You can use universal O2 sensors. I believe there are quite a few members here who have done exactly that. There's some simple harness connector splicing involved but that's it.
One thing to keep in mind is that cat and O2 sensor codes can cause each other and even stand in for each other. If the cats are bad, O2 sensors can show as bad. If the O2 sensors are bad, the cats can show as bad. They're interdependent. It's entirely possible that only one or the other actually needs replacing. The big "but" here is that your O2 sensor code is for a bank 1 (rear bank) sensor while your cat code is for the bank 2 (front bank) cat.
How did the emissions people determine that the cats aren't heating up? Merely by seeing the codes?
I would try replacing the oxygen sensors (upstream on bank 1 and maybe even downstream on bank 2 as it MIGHT be causing that cat code) to see if things look okay at that point...since that's the cheapest step. If that doesn't work, I'd move on to replacing the cats.
And just in case you're not aware, part of the reason 2 aftermarket cats wouldn't pass emissions (regarding your prior cat replacement) is that there are two more converters integrated into the exhaust manifolds. Those are the pre-heat cats which help cold-start emissions and help get the main cats up to operating temp faster. But unless your OEM pre-cats are bad, replacing only the main cats shouldn't actually impact emissions. You may still be absolutely fine putting two aftermarket cats on. If replacing the O2 sensors doesn't change anything, though, that is a sign that your precats could indeed be bad.
One thing to keep in mind is that cat and O2 sensor codes can cause each other and even stand in for each other. If the cats are bad, O2 sensors can show as bad. If the O2 sensors are bad, the cats can show as bad. They're interdependent. It's entirely possible that only one or the other actually needs replacing. The big "but" here is that your O2 sensor code is for a bank 1 (rear bank) sensor while your cat code is for the bank 2 (front bank) cat.
How did the emissions people determine that the cats aren't heating up? Merely by seeing the codes?
I would try replacing the oxygen sensors (upstream on bank 1 and maybe even downstream on bank 2 as it MIGHT be causing that cat code) to see if things look okay at that point...since that's the cheapest step. If that doesn't work, I'd move on to replacing the cats.
And just in case you're not aware, part of the reason 2 aftermarket cats wouldn't pass emissions (regarding your prior cat replacement) is that there are two more converters integrated into the exhaust manifolds. Those are the pre-heat cats which help cold-start emissions and help get the main cats up to operating temp faster. But unless your OEM pre-cats are bad, replacing only the main cats shouldn't actually impact emissions. You may still be absolutely fine putting two aftermarket cats on. If replacing the O2 sensors doesn't change anything, though, that is a sign that your precats could indeed be bad.