Emissions code, 2000 Toyota Tacoma WHAT TO DO?

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  #1  
Old 05-14-06, 03:11 PM
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Emissions code, 2000 Toyota Tacoma WHAT TO DO?

2000 Tacoma, 2.4L, 94K miles, 5sp manual.

I am getting emissions code P0420, which according to what I've read on the internet, means I either have a fautly O2 sensor, faulty coolant temp sensor (what the?) or a fautly Cat.

So how do I narrow it down to one without having to replace them one by one to find the problem?

Thanks, and also please look at my other post about my wife's car if you're good with EVAP codes...

http://forum.doityourself.com/showthread.php?t=263977


Thanks,

Matt
 
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Old 05-14-06, 04:27 PM
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I thought a P0420 was the cats are operating below threshold
At least that's the computer thinks

I suppose a faulty O2 could set that one off by false readings, but I don't believe P0420 is a "Faulty O2 Sensor" code

The coolant temp sensor....I don't know where that one came from
 
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Old 05-14-06, 05:16 PM
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What the computer is "seeing" is the speed of the O2's toggling rich/lean in frt and behind the cat convertor........If the speed varies too much it calls a 420..............NOW. It COULD be a faulty O2.........and the way to determine that is to use an infrared temp sensor on the frt and rear of the cat...........Big variation in temp and you've got a bad cat......If the temps are close you have a sluggish O2
 
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Old 05-14-06, 05:40 PM
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I have access to an infrared temp sensor that we use to check the operating temp of some high-frequency routers at the cabinet shop.

What do I need to do, get the engine nice and hot and check the temp directly in front of the cat in the exhaust pipe and directly behind it? What sort of difference in temp is "big"?
 
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Old 05-14-06, 09:39 PM
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Originally Posted by mako
2000 Tacoma, 2.4L, 94K miles, 5sp manual.

I am getting emissions code P0420, which according to what I've read on the internet, means I either have a fautly O2 sensor, faulty coolant temp sensor (what the?) or a fautly Cat.

So how do I narrow it down to one without having to replace them one by one to find the problem?

Thanks, and also please look at my other post about my wife's car if you're good with EVAP codes...

http://forum.doityourself.com/showthread.php?t=263977


Thanks,

Matt

You can take it to the dealership , for a fee they'll do a complete scan that'll take the guesswork out of it they usually charge about $ 100 but like I said it's worth it because they pinpoint the exact problem unlike those scanners that only give you a general idea or starting point.
 
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Old 05-16-06, 06:06 PM
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Wrench47,

I used the infrared today. The pre-cat temp was around 285 and so was the post-cat temp. So according to your advice I suspect the cat is fine (that, and the exhaust comes out with a distinct throb instead of a sickly wheeze like I've seen on other vehicles with a choked cat).

Based on this assumption, the guess of two friends that are mechanics, and some other info I've read online, I bought a new upstream O2 sensor. The worst that could happen is I have a new O2 sensor.
 
  #7  
Old 05-17-06, 01:30 AM
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Well then its possible that the oxygen sensor is the main culprit. IN case replacement is needed, online stores are around..and they're a better choice as compared with tradional stores. That's based from personal experience.
 
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Old 05-17-06, 05:04 AM
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keep us up to date

Please keep us up to date on the cause of your code as I also have a Tacoma 2004 model same engine and trans setup.
 
  #9  
Old 05-18-06, 06:46 PM
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Replaced the O2 sensor today with a Bosch.


Anyhow, the original was pretty caked. I've replaced a handful of O2 sensors before and never saw one like this, but those were older model early 90's vehicles so not sure what the difference is.....

Click the link to see the pic. Reckon this was the culprit? I erased the code and drove it 6 miles or so, I could definitely tell it idled and accelerated better (smoother).
http://img.villagephotos.com/p/2005-...nsortacoma.JPG
 
  #10  
Old 05-21-06, 09:34 AM
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Replaced the O2 sensor (very, very easy and didn't even need to raise the truck any, just wedged myself under it well and it took 15 minutes total).

Drove a normal commute to work, total 40 miles, and then drove a 400 mile round trip for a family wedding and the light did NOT come on. Before I replaced it, the light would come on within 10 miles of clearing the previous code. I'm sure this solved the problem, 500 miles later no emissions code.


Thanks,

Matt
 
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Old 05-21-06, 04:29 PM
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outstanding

Good deal on the fix any special tools? and how much does a sensor cost for the truck just in case I might need one.
 
  #12  
Old 05-22-06, 05:07 PM
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The only tool you need is a good wrench (I forget the size but it's a fairly small nut you remove).

In the past, the sensor's I've changed went in just like a spark plug..... you screw it in and plug in a wire (snap connectors).

This one was a tad different---- the exhaust pipe had two posts sticking out of it that the O2 sensor went in between-- the sensor has a base plate on it that the posts slide through. The nuts thread over the posts and bite the baseplate to the exhaust, and thus secures the sensor. Is simpler than I make it sound, just look at the pic link I posted above of the old sensor and it'll make sense.


Cost at Advance Auto was $130. I may have gotten it cheaper elsewhere but I haven't the time at the moment to shop around.
 
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Old 05-22-06, 05:17 PM
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I see

OK I see the pic of the old one and understand it Thanks for the info hope my Tacoma goes many many miles before I get problems,
 
  #14  
Old 05-22-06, 05:48 PM
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This is the first one I've had and I have 95K miles on it.


Actually, I did have a problem with it at 60K miles. It would not crank, as if there was no juice reaching the starter. Checked everything.... finally narrowed it down to ME. I had accidentally kicked & damaged the "dead mans switch" at the clutch--- the switch that opens the circuit to the starter when you press the clutch. Had I read the engine codes, they would have said "User Error: Please Replace User".
 
  #15  
Old 05-22-06, 05:56 PM
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I do not like that switch

I know what you mean about the clutch switch many times when I had the seat to far back and I turned key nothing would happen because I did not have clutch in far enough.
Once I get out of warranty I will figure away to bypass the thing.
But since it is a 2004 model with only 12 thousand miles I will not mess with it.
I have had good luck with Toyota cars so I bought a small pickup because that is all I need and with the price of gas these days all I can afford.
 
  #16  
Old 09-06-06, 12:41 AM
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catalyst

if the converters turn out bad. they have 8yrs/ 80,000miles warr per fed gov . also the ECM has same warr.Thats all cars & trucks sold in the USA.
 
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