Being a 2002 you have a 2 cat system right?

 

Here's some more info:
http://www.tacomaterritory.com/forum...ighlight=p0420

 

Another interesting thread on the p0420:
http://www.tacomaterritory.com/forum...ighlight=p0420

 

I just got the PO420 code as well. I read on another site that over-oiling a K&N air filter could cause this problem, and I recently cleaned and oiled mine. Does anyone have a write up on how to clean the MAF? Or any other suggestions?

 

Yeah, I saw that too. I guess its posssible if the MAF was dirty throwing off the A/F ratio that the cat/cats would have a harder time scubing the exhaust of bad stuff.

There are lots of threads about cleaning it, take it out and spray it down with electrical contact cleaner or some say brake cleaner works better. I've just used electrical contact cleaner. Don't touch the sensor wire with ANYTHING else, don't even use a q-tip on it, just spray it.

My suggestion is to get rid of any oil entrapment style air filters, especially with vehicles that use a MAF for air flow metering.

 

Ok well the code came back,,,, I just don't know where to start.


aaron

 

Well the damn light came on again and well I can tell a slight full consumption increase. Not Cool! So I talked to my mech and ordered the URD dummy box and will start there. From my research even with an after market cat it is still possible to trip the ECU, so the 1st step is URD o2 deally, then a cat. And I might just buy a OBD II unit.


Aaron

 

That should do it, I haven't had a P0420 since putting one on.

Not sure if it will help with MPG though.

 

Damn I hope so! I was getting 18mpg clean, keeping her at 2400 +/- 100rpm's. I gained the mpg back from the gears. I'm going to be s pissed if it doesn't. Though if it simulates the same numbers the oe cat is supposed to produce the ecu won't try and compensate and trip the CEL. In theory!


Aaron

 

ok my codes are coming up as P0130 and P0133 any one know if its the fron or the back o2 sensor?

 

Front.

 

Alright well as you know i have the p0420 code, and purchased the URD os simulator. Well all is well with the order of the simulator but the darn instructions are baffling. I looked on TIS but can't find the diagram for the ecu. Any ideas. And for the record my 02 ECU is not located behind the glove box. It is on the D side under the dash.

Aaron

 

Ok Im on tis but cant find anything on ecu pin out. I'm trying to find the right wire to cut because my info doesn't match URD's

 

Better contact URD on that. I'm pretty sure mine came with vehicle specific instructions. Toyota made wiring changes year to year sometimes.

 

OK - I have a 2000 4Runner with 115,000 miles. It is a 4x4 and is running great. The other day the CEL came on with a P0420 code. I reset the ECU and it came back in a day or so. I have access to a BR-3 OBD-II scanner but I'm not sure what to make of the data. I can see both sensors (this is a CA Emissions vehicle - two EXPENSIVE CATs) but not sure what they should look like as far as the waveform goes.

The O2 sensor (or A/F sensor) before the first CAT is pretty flat as far as the voltage goes - rarely moves much even under load.

The O2 sensor after the second cat does go up and down but then sometimes goes flat (the voltage). The fuel trim just sits at 100.

Anyone good at diagnosing this? I have the log files if anyone has the same scanner or has downloaded it.

The CATs on this truck is outrageously expensive. The dealerships that I have talked to say that they cannot determine which cat is bad which means replace both for a truckload of money. I can't afford that.

Thanks for your help.

 

Wow, I didn't know they would go that high, is that the long or short term trims. Positive or negative?

 

I apologize - a snapshot of the graph is attached.

 

I think I confused myself. The Short Term is 1.6 and the Long Term is -0.8. That is at an idle - 0 MPH. Pretty much the same at 10-35 MPH. I logged a lot of data ... still plowing through it.

 

Nothing wrong with those trims, looks great.

 

Thanks... I'm starting to understand what a lot of this means. Awful lot of data.

Did you check out the pic in the previous post? Does that look "normal"?