O2 Simulator or Replace Cat?

Did you also have to change out the fron A/F snesor and the O2 sensor? or are you using the OEM sensors? I keep hearing that you need to use OEM cats, to eliminate throwing the PO420 code...

 

You don’t need the OEM cats to eliminate the 420 unless you bought a cheap cat.
Sensors don’t need to be replaced unless they are defective.
The OEM cat is far more superior than any aftermarket cat
https://densoautoparts.com/find-my-part.aspx

 

This is why non technicians like me always watch fuel mileage. Many times it’s the first symptom of early engine trouble.

 

Nope I didn't have to change the sensors. The Carb approved Magnaflow cats meet the 50 state standard just like the OEM ones do, though probably not to the same degree. But that's why OEM is a grand and Magnaflow is a few hundred. But I've been running them for 3 years now and no more p0420 code

 

I actually bought a used OEM cat as a spare just in case

 

can you make a recommendation on aftermarket cats?

edit - ok, i see magna flow is referenced.... any other suggestions (i didn't see magna flow on rock auto).

 

I’ve never needed a new cat, so don’t know

 

I've always heard Magnaflow is the best aftermarket brand which is why I went with them. Followed by Walker which I think Rock Auto does sell

 

Thanks for this. I looked over the magna flow site, it's asking if my truck is CA compliant... see attached pic of my tag, i'm assuming it is... looking for confirmation on that. If so, that's kinda weird, b/c my truck was initially sold in Rochester, NY

 

My 2000 Tacoma originally sold in Virginia is California compliant, not all were . My understanding is that from 2001 on, all vehicles were California compliant.

 

got it. makes sense.

 

I found all this out the hard way by ordering emission parts for my 2000 Tacoma. Making a long frustrating story short, I found out I have a California compliant vehicle sold in Virginia, I have two very expensive catalytic converters instead of one and my rear O2 sensor was more money also ☹️

 

The line that says "...and to California regulations applicable to 2004 model year new LEV-1 LEV light duty trucks"

That means the truck meets california emissions standards. My sticker looks different, I'll take a picture later.

 

I was showing the P0420 code, I only drive my truck 3-4,000 miles a year and money was tight so replacing two converters was not an option at the time.
I went on YouTube and tried the $4. Resistor / capacitor trick wired to the front O2 sensor and tucked it up under the passenger seat. The light is off now over a year.

 

Do you recall the value of the capacitor you used? I'm seeing a couple different types on the vids, not sure it matters much other than the time to charge it, but wondering of there's something optimal for Toyo... Thanks.

 

4.7uf capacitor

1 Mohm 1/4 watt resistor

 

perfect. thx.

 

Hoping you can assist... I wired this up, and reset the monitors. No P0420 yet, still waiting for the CAT monitor to set, but now I'm getting P0136 for the o2 sensor. Pretty confident I wired this right (capacitor after the resistor, etc). I checked the live data stream with a buddy's scanner, and I'm getting a steady 0.485V (with the circuit mod). Previously, I was getting 0.8V - 0.85V (and was tripping the P0420).

Does the o2 need to be right at 0.5V to avoid the P0136?

 

On the wires coming from the (new) #1 Bank Denso O2 sensor.....I wired my resistor in-line on the blue wire and after the resistor I wired in the capacitor between the blue and the white lines. The two black lines are left untouched.
( Interesting to me was .....if I left the (new) #2 Bank Denso O2 sensor in I couldn’t get rid of the P0420, I put the old 130,000 mile O2 sensor back in and no code for over a year now )
Sorry I can’t be of more help. Hopefully someone more knowledgeable will chime in.