Check engine codes

I am working on my son's 02 prerunner and I noticed his check engine light is on.
I will run up to the local parts store and get the guys to scan it.
Does anyone have a list of the codes so when they pull it I can see what it is?

Thanks in advance.

 

http://www.obd-codes.com/trouble_codes/toyota/
http://www.troublecodes.net/Toyota/

 

I removed the neg. batt. post to see if it cleared and so far no light back on.
We will see if it returns.
Thanks for the quick and very informative info.
I appreciate it.!!

 

You may have cleared the light, but the trouble code may still be stored in the computer. Get the code(s) read and find out what's causing the CEL.

 

Will do!
Thanks again for the great info.

 

I'll tag this to see if the light comes back on. I have access to all the codes, and flow charts for diagnosis.

 

they run codes for free????? orileys, napa, advanced. wheres the place to go?

 

Gentlemen,
You were correct. The check engine light did come back.
P0420 The place that read it say's it is "Cat system efficency below threshold (bank1)

About a year ago he had the rear cat hacked by thieves out and we had a muffler shop replace it ( not with a Toyota ).
Is it possible it is the front cat on bank one?
I am new to these engines which side is bank one?

Or is it most likely the back cat that was replaced.
Truck has apx 91K on it for miles.

Is it likely the sensor is not working correctly?
Does that happen very often?

 

Usually its the sensors... I just had the same code, and figured out that cat's were still good, and then changed both sensor's and now all is good!
I would start with the sensor's. But with this code it can only be 2 things, cat's and sensor's. Usually...

 

My son has the truck now, is there 3 sensors total? or just 2?
Would you happen to know the part numbers so I can pick them up and do the truck without tieing it up for too long.
Thanks again.

 

Don't you want to make sure it's the sensor s that are giving you the problem before you change them out? BTW, there should be 2 of them, one before and one after the catalytic converter.

 

There are 2... ^^ Yeah, do check and see it is indeed the sensors. Usually you can just tell by looking at them. Like mine were very black, and had burnt spots on them. (Indicating bad)
Usually o2 sensors should be replaced around 80-100k miles bc they are a wear item, and your mpg's and trucks performance will suffer.

Or you can have a shop check them out.

 

Thanks guys I will pull them out as it is 90K miles and see if they ar messed up.
Much appreciated.

 

Like others said, don't go replace sensors just yet. The factory shop manual says check for 1) exhaust leaks first 2) sensors 3) cat

I had this code not long ago, and in checking things found a big exhaust leak just after the cat. Fixed the leak and turned off the CEL, and it hasn't come back yet. Total cost - $0. Not saying that's what it is, but eliminate that first before buying any parts.