Cel

[three]

Does anybody else have any problems with the check enging light staying on. I had it scanned and it tells me that the rearmost o2 sensor is bad so i buy a new one and still same thing. Mazda basicly said screw you and wouldnt touch it. Any suggestions on what next.

 

[goldwing2000]

Is your car still under warranty? It sounds like there's a deeper issue.

 

[three]

The dealership told me that the cold air intake and exhaust voided the warranty and that they could not touch it unless i had all factory stuff on there.

 

[goldwing2000]

Ah. Yes, they are correct.
What exhaust did you put on and what parts were replaced?
Do you still have both cats?
Did you pull the MAF wiring harness away from the battery box?

 

[Mazda3GQ]

9 out of 10 times you get a 02 sensor code is because some OTHER part is effecting its readings.

When did it start happening? Was it after installing any certain part or parts?

 

[tsunami]

o2 sensor... prob something to do with the exhaust not the cai i would think, and if you took off your exhaust you had to cut it, so it can't be put back on...

 

[three]

It all started happening about a month after i put the cai on. My MAF is alrite, already checked on it. It kinda feels like its missing every now and then. Like ill be goin down the road and it will just feel like i lost all my power suddenly then it will pick back up all in about a second.

 

[LIAxela]

did you try resetting the ecu?

 

[briand805]

It all started happening about a month after i put the cai on. My MAF is alrite, already checked on it. It kinda feels like its missing every now and then. Like ill be goin down the road and it will just feel like i lost all my power suddenly then it will pick back up all in about a second.

Check all of the pipe fittings. make sure there are no leaks..

I picked up one of these for $170 brand new on ebay.
http://www.canobd2.com/tool/OBDSimple.asp
simple and extremely easy to use.. No need to connect to a pc unless you want to print out the info.. I like it because when your throw a CEL it takes a snapshot of several variables EX: throttle position, intake pressure,coolant temp etc..

 

[three]

I reset the ecu all the time but it just comes back in a day or two. Someone told me that i could be because my o2 sensor isnt behind a cat anymore so im thanking bout moving it behind the second cat and maybe trick it.

 

[goldwing2000]

If you removed the front cat, then that's definitely why it's popping a CEL.

 

[Mazda3GQ]

by removing the cat, you changed the back pressur of the engine which changes the A/F ratio of the engine as well. The sensor is prorammed to look for specific range of readings and now the car going out of the norm. This is why the code is thrown. People usually reprogram the computer or install something to trick the computer. Or they realize that a good high flow cat is sometimes better if not as good as no cat and just put it back.

 

[tsunami]

(thumb) like i said exhaust... (thumb)

If you removed the front cat, then that's definitely why it's popping a CEL.

 

[three]

It has been throwing the cell since long before i installed the header. Right after the Cold air intake. I know it cant be anything too bad kuz it was missing bad after i installed the CAI, then after the header it almost completely stoped. Maybe ill get a high flow cat and test that view. maybe it just needs more fuel kuz its got enough breathing but stock fuel system.

 

[Je5ter]

My dealership told me adding a coldair intake would NOT affect my warranty??

 

[Solo2Protege]

well, if it happened right after you put the CAI on, wouldn't that tell you the CAI is the cause. If at the time the exhaust was stock, the CAI is the problem. Almost all CEL's with an intake will throw the O2 code (P2906 or something like that)

so you've been driving around all this time with a CEL?

 

[peepsalot]

what is the exact code.

 

[three]

I already checked to see if the intake caused it. I put all the stock crap back on and it still had the CEL. The guy didnt have a printer. Dont remember the exact code but it was something like low temp and o2 sensor something or another.