irked

After my CEL came on this last weekend I had the codes checked and got 120 and 420 codes. Unfortunaley I had my catalytic converter stolen last year and had to have a new one put in. The thief was kind enough to not cut out the sensors.... I'd really like to think none of this is related to the converter with it being just a year old.

I've used search just enough to have found the Tacoma repair manual (thanks to whoever posted) and now know to check the TPS and oxygen sensors with an ohmmeter (haven't done that yet).

With having both the TPL and sensor codes is it more than likely going to be a TPL problem which in turn is causing the sensor codes?

I'll keep looking through the forums to avoid asking too many ignorant questions, but in the meantime any comments or suggestions would be greatly appreciated.

mt_goat

What year and model vehicle do you have?

The P0420 could be from the replacement cat for sure, new or not, but we need your vehicle info.

irked

Doh....

1998 3.4L 4Runner.

mt_goat

I'm not sure but I guess that year is a one cat model. What state are you in?

If you don't have a problem with emissions testing these work great (I have one) for just getting rid of the P0420 CEL: http://www.urdusa.com/index.php?cPat...35i9ms5p2654c1

I've never had to deal with a P0120 (Throttle/Pedal Position Sensor/Switch "A" Circuit) but you might try a new or different TPS or at least check the wiring connection to it.

Good luck

warriors_03

TPS's are really cheap. something like $40. I would try changing that first, and see if that alleviates the problem. Then move to the cats.

On a side note, I had a p0420 code myself for a long time, and refused to believe it was my cats. Well, I ended up putting in new 02 and AF sensors, which corrected the p0420 code and then threw a lean out code, which ended up being the MAF sensor. Long story short, since your cats are new (are they factory??), I would have a hard time believing that they are bad.

You can get the parts from trdparts4u.com (toyota of dallas) for discounted dealer prices, and they are really nice people.

PM me if you have questions.

Mark

irked

I'm in Missouri and it is a single cat (was replaced with oem).

I did put a new TPS on and had the codes checked again but unfortunately I'm still getting the 120 code.

I think I'm at the extent of my troubleshooting abilities and to the point of fixing the CEL with some electrical tape or breaking down (no pun intended) and taking it the the local Toyota stealership. Looking in my wallet the electrical tape appears to be the better option.

Thanks for the suggestions, guys.

irked

...and then I pulled my head out of my arse and disconnected the neg. battery cable. All is good now!

ARK_SWAMP_RIDER

Yea, you can clear the computer by disconnecting the cable. On the flip side, if you get the p0420 code, here's a suggestion. I don't know how this applies to your vehicle, but I've got a 96 Mustang Cobra w/o cats. I was getting that error code. I fought it for a while before I found a cheap/easy solution. Go to your local auto parts store and purchase some spark plug non-foulers. Here's a complete write up:
http://forums.evolutionm.net/evo-how...ouler-how.html
I know for sure this has worked on a variety of vehicles, including mine. From what I've been told, all the o2 sensors are the same diameter, so you should use the same size non-fouler as what's listed in that link. It's worth a shot, if it doesn't work you're only out a little time and $5. I've yet to hear of it not working for anyone. I know that doesn't fix the cause, but it sure saves some money as a temporary solution if nothing else. Would you happen to have an exhaust leak? I've been told that could cause the code as well, so it may not be your cats.

mt_goat

That won't work with Toyota O2 sensor bungs, the O2 sensor doesn't screw in. They have two studs like this:

ARK_SWAMP_RIDER

LOL, like I said, I've known it to work on several other makes/models, but haven't heard of anyone trying it on a Toyota (for that reason). It was worth a shot at least.

mt_goat

There may be a way to adapt a screw in sensor to the studded bung but then you would also need a screw in O2 sensor. Like I posted earlier there are simulators you can buy, or if you're cheap and want to make one I can post instructions for a DIY simulator.