I recently switched from a Test pipe with a sim fix to an SMSP convertor.
After the install, it threw a CEL. Hooked up the OBDII scanner and it said it was for a bad 02 sensor. A few days goes by with the light on and last night I noticed the CEL was no longer there so I drove around for awhile to see if it would reappear. It didn't. Today the same thing. No CEL.

Does this sound right? Do 02 sensors "come and go"? Why would the scanner say its bad and then a few days later the CEL corrects itself without resetting the ECU.

 

It's happened to me before. It's best to replace the sensor, because it may not be throwing a code, but it may not be functioning properly.

 

i woudlnt worry about it too much. if the cels gone then i think youre good to go. cant give you a great answer to the o2 coming and going. even with the cel it doesnt effect the tune

 

Mines been doing that for the past year. Itll be on for a month then off for two then turn on again a few months later and be off the next week. Might have to do with the weather but who knows.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GO-FIGHT-KILL &raquo;</TD></TR><TR><TD CLASS="quote">It's happened to me before. It's best to replace the sensor, because it may not be throwing a code, but it may not be functioning properly.</TD></TR></TABLE>

As its the secondary 02 sensor, it won't hurt performance. It's only job is to check to see that the cat is properly doing its job.

 

That's reassuring. I'm gonna be pissed if I have to buy a new one since this only has less than 5k miles on it.

 

exactly what i meant. neo just worded it better

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by get RIGHT &raquo;</TD></TR><TR><TD CLASS="quote">Hooked up the OBDII scanner and it said it was for a bad 02 sensor.</TD></TR></TABLE>

Which O2 sensor was the code for? If it was telling you that it was for a bad primary O2, the fact that it eventually cleared after switching to the cat makes sense.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Padawan &raquo;</TD></TR><TR><TD CLASS="quote">

Which O2 sensor was the code for? If it was telling you that it was for a bad primary O2, the fact that it eventually cleared after switching to the cat makes sense. </TD></TR></TABLE>

The title of this thread is: "Secondary 02 Sensor Acting Strange"

 

Touche.

It just seemed odd that the problem coincided so closely with the installation of the cat, and the secondary would be the only one that was touched during that process.

 

Plug the hole in the cat with a bolt (I used a large spark plug) and push the sensor through the wire hole in the body (wrapped heavily in foil to insulate heat). This is a proven way to trick the ecu.

If the problem still comes and goes, it would obviously be the sensor, but if it no longer acts up, I would place my bet on the hi flow (assuming it is) cat.

Sound reasonable?

Or go the expensive route and buy a Hondata S300. Load the ITR base map and disable the secondary o2 sensor.

 

When doing a high flow cat or test pipe the secondary o2 sensors is supposed to check the difference in pressure between it and the primary o2 sensor on the header. The test pipe flows so fast that you have to trick it , by getting it out of the stream of the test pipe. cel engine light eliminator kit is always not the answer, shim it out of the test with two 18mm spark plug filers, or put a plug in the test pipe and tie it up some where in or outside of the car.