Nooget

Hey, everyone -
Just got an 02 EP3 that's showing a CEL, which the previous owner tells me is from the DC race header (catless). I scanned the car and got P1166, which is the primary O2 sensor. The previous owner had used the defouler trick for the 2nd O2 sensor, but was still getting a CEL. I had the defoulers replaced with the Megan O2 (mechanical) sim today and am still getting the CEL, which makes sense if the defoulers weren't working, but I thought it was worth a shot.

My question: does the ECU usually throw the P1166 code?? Seems like it would be showing a code for the downstream O2 sensor, not the primary O2 sensor. I'm just wondering if the defouler and Megan O2 sim have been doing the job and the primary O2 sensor was bad all along. All the connections to the O2 sensors seem to be tightly connected. The car does have 95k miles, so it seems possible that the primary O2 sensor would go out.

Any help would REALLY be appreciated. I need to pass emissions so I can register the car. If nothing else, anyone in Albuquerque know of an emissions tester that I can bribe? haha

cloumep3

How long did you wait til' you did the latest scan? It needs some time before it actually refreshes/clears the code, if the defouler was the issue that is... Also, you may already know, but the time it requires for the code to clear varies from one car to another, depending on the drving condition. I know it my old whip, it took about 200 miles or so to clear whereas one of my buddys took about 300 miles or so to clear the CEL.

Nooget

Well they cleared the CEL with the OBDII scanner when they installed the megan O2 sim today. It came right back on, I drove it home, then scanned it again and came up with the same code. If I clear the code, it pops back on after about 10 seconds of the engine running...

nahonda04

your primary o2 sensor has gone bad....replacing the defouler for the secondary o2 sensor will not help you because it is not the sensor that is bad...unfortunately you cannot do any "tircks" to fix the primary o2 sensor CEL...you must replace the primary o2 sensor!

Nooget

Well, I know it's not the best way to go about solving an issue, but I bought a new primary O2 sensor...just waiting for it to come in the mail. I'll give you guys an update once I've installed it. Hopefully it takes care of the CEL!

rjmq06

ei i have a CEL on too, does anybody know where to find a check engine light codes or list thanks

Nooget

Just google: Honda OBD ii codes
Or, if you have the specific code, I can check my Helm's and tell you what it is...

rjmq06

yeah thanks bro
i check my cel this morning and it gave me P0420 which is a 02 sensor idk if its the primary or secondary

rjmq06

if your from los angeles i can help you to pass the emission

Nooget

I'm in Albuquerque, but thanks for the offer. Per my Helm's, P0420 is P0420 "Catalyst System Low Efficiency" -- do you have a race header/test pipe or anything? If you do, you should give the defouler trick a shot. If not, it might be time to replace your CAT.

rjmq06

my car is all stock so maybe its time to change my cat

Nooget

Just an update for anyone else that might eventually come across the same code: I replaced my primary O2 sensor with a brand new one from Denso and the CEL went away and hasn't come back! Woot!

One more question:
I've heard that after clearing the CEL, your ECU needs to run through a few cycles before it will have enough data to pass emissions. Any idea if this is true? If so, how long/far should I drive it before taking it to get tested?

rjmq06

damn i didnt know that 02 sensors are effin expensive anyway where did you get yours?
do you know any cheap place?

cloumep3

It all depends on..., your ECU has different criterion that must be met and depending on your driving habit or schedule, it may take just 50 miles or you may need to go 200+ miles. On my old IS300, I had similar issue and after installing O2 Sim, it took me about 100 miles or so for the cycle to clear. Best way to do is just keep on scanning until all cycle is cleard; that's what I did, once after 50 miles and second time right after 100 miles. GL yo!!!