2005 mt 55k miles. I just put a full AP exhaust on the car (okay, the Jew did). Too loud for me, and I didn't like the CEL, so I took the midpipe off and put the stock caty back on. This is supposed to lose the CEL, right? Ok, not.

After going through the steps, the CEL goes out the first time I start the car and stays off as long as the car is still running. But once I shut it off, next time is CEL time.

So here's what I've done after reading about it:

1. Disconnect battery for 25-30 minutes.
2. Reconnect battery.
3. Turn key to "on" position.
4. Turn wheel to far right, then far left until DSC OFF light goes out.
5. Turn key to "off" position, then start car.

Then I tried this:

1) Start the engine and warm it up completely. This means allowing one full cooling fan cycle. During warm up, make sure all accessories are turned off.

2) Idle the engine for more than 30s after the cooling fan has stopped, then turn the engine off.

3) Re-start the engine and drive the car in the following fashion:
A) Idle the engine in neutral for more than 7m35s.
B) Drive in first or second gears, between 25-46 mph, for more than 30s.
C) Drive in second or third gears, between 38-62 mph, for more than 20s.
D) Drive in fourth or fifth gears, between 32-62 mph, for more than 2m.

It is said in the Mazda repair manual that this procedure allows the PCM to measure all that it needs to ensure no further CEL's unless there is an outstanding issue.

CRH

1) With the key in the off position, press and hold the odometer reset button and turn the key to on;
Continue to hold the odo button until the odometer reads "TEST" and then release.
2) Turn the key to off and repeat step one.

This will reset the entire PCM except the KAM which contains the sensor profiles amongst other things. You can reset it with the familiar procedure:

1) Turn the key to on
2) Depress the brake pedal rapidly 20 times in a row until the oil pressure gauge sweeps to halfway and back again.

Am I missing a step? Argh!

 

 

Are you sure the cel is being caused from the CAT? (Rear O2 sensor)
Go to autozone and get them to read and clear the cel

 

you need to know what the CEL is for. could be unrelated - like your gas cap being loose or leaking

 

Without knowing the CEL...you are just guessing what the problem is...

wcs and others are right...figure out WHAT the code is before you try and figure it out

 

Guessing is so much harder over The Intertubes......

S

 

Yeah, I know. It just seems way too coincidental for it to be anything else. So Autozone reads codes? I don't even know what that means, but I guess I can try it.

 

Driver's side O2 sensor.

 

?? There are only 2...one is the main WBO2..and the other is the narrow band rear sensor....

Check the plugs and wiring....they have been known to melt

 

I believe it's the front. "The one past the cat."

 

Front is before the CAT...rear is after....

 

My bad. He described it to me weird. Weird to me, anyway. It's the rear. The easy one. I'll have it Tuesday. Hope that does it. Thanks for chiming in.

 

just go to the dealer becaause i get the feeling you might do more damage than good (no offence ) but they can fix it alot faster than any other place with less frustition and headach

 

Thanks, that's normally sound advice, but I can at least handle the sensor. It's fixed.