I'll start by saying repairs were done with a non-consult OBD-II reader.

Also, I have replaced the MAF last year and had a software upgrade as long as all ignition coils.

Now recently my light went on. It pulled a rear O2 code. Had that fixed with a Bosch sensor. After awhile the light went on again. Catalytic was then replaced under warranty. Drove around again. Light goes on and this time Bank 1 front O2 sensor, so I decide to replace both front O2's with Bosch Universal sensors. Now the light has just come back on.

What could the cause be? I haven't gotten around to pulling the new code. Does the ECU need another software upgrade perhaps with the new O2's? Or do I have to reset the ECU by disconnecting the battery as opposed to using the regular OBD-II to clear it?

Any quick help is appreciated as I am getting annoyed of constantly paying to fix this car.

Thanks,

 

You need to get the new codes for a proper diagnostic. As an aside, resetting the ECU will not nessarily clear the code. However, it can't hurt to do both. Clear the code with your scanner and reset the ECU and see what happens.

 

You need to have the code pulled, if you don't do that we really can't help.

As far as resetting the ECU... Simply disconnect the battery for a few hours and the SES light will be off. The code WILL still be stored, you need to drive around and allow all the diagnostic test to run before the code will really "clear" from the ECU.

If there is still a problem, the SES light will pop back up, have the code pulled and go from there.

 

You see what was done there, almost like a pattern.

Without that information, we cannot provide any reliable/educated help, quick or not.

Side note:
Don't let SES lights ruin your modding fun, I know I sure as hell don't.

 

Problem solved. Another P0420. He then ordered a direct fit OEM spec catalytic (cheaper then $700cdn Nissan one but same specs). Now light is gone and I passed my emission testing with flying colors. If anyone has this prob and put in some sort of Universal aftermarket Cat, you will continue to get the code and run very lean.

 

on the lean theory re: changing cat.

Cliffs: Cat wont cause lean condition.

 

I was told my car is running very lean, but oh well, it still caused me to fail emision testing badly. 1180 NO PPM (whatever that is) out of 450 and that was a new Universal. They put in a direct fit and I got 330.

 

Hmm, if it is from a tailsniffer, it will read lean due to the cat, and depending on the condition of the cat, it might even amplify said lean reading if the cart is damaged/old, etc.

 

Yes tail sniffer is used for our e-testing.

The Universal was put in during the spring. Due to recent e-testing woes they replaced it for free with another. Still no luck. They then put in a direft fit OEM replica and I passed with flying colors. Mech said it could be due to my Y-Pipe and not having the pre-cats could cause the Universal's not to read properly. Oh well. It is all good. Car runs great now, and this will not stop me from modding .

Knock on wood car should be fine. Within the last 2 years I've replaced the MAF, all 6 coils, all 3 O2's and now a proper cat.

 

In Texas, as long as the SES light is off when they plug in the reader, you pass if you have an OBDII car. OBDI and earlier get the tailpipe sniffers.

 

For us no test is required in the first 5 years of a car. Then you need to do it every 2 years and then I forget the age and it becomes every year. Every car gets the tail sniffer.

I'm just glad everything worked out and they pinpointed the Cat. Can't believe I've been driving the car like this for over 2 years with no codes but just recently the code came about. It was on and off before.