Check engine light not fixed by replacing o2 sensor??

Hello,
I am new to the forum but have heard really good things...To sum up my issue. I bought my second taco from a guy a few weeks ago and the check engine light was on...he told me it was the downstream 02 sensor which I bought for 100 bucks and replaced thinking this would solve my problem. I them went to advance to have the code turned off and it showed P0440 and a few others I cant remeber. The truck runs really good and seems to get good mileage- no sputters or lags...just wondering what to do next?? I am praying to god it is not the cat. I have a 30 day tag and will be registering the vehicle in TN where I do have to pass emissions. Any Ideas??

 

Where did you get your sensor from? I've heard non-oem sensors are hit and miss.

Anyway, Welcome to TW!

 

Look up what the codes mean first. Otherwise you're just replacing parts at random. What generation Taco is it?

 

The part was a Bosch I bought from Advance and it was a direct plug in. Also the truck is a 2002 V6 TRD. The install went clean...did I mention the guy erased the code and it came back in about 3 minutes?? not sure if thats relevant....I will go tommorrow and check the codes again. Does anyone know what code comes up if the cat is bad??

 

Are you saying the P0440 code came back on in about 3 minutes? Or that the light just came back on in about 3 minutes? It's VERY unlikely that you could set an EVAP code that quickly after clearing it... it takes the computer longer than 3 minutes to perform the evap test... and it's 2 trip logic so just failing the test the first time won't turn on the MIL.

A bad 02 or A/F sensor could very likely still be the culprit here, however you need to provide us with what codes are stored in the system. It's also very likely that the 'guy' you bought the truck from diagnosed the wrong sensor as being bad. More info would be beneficial to you

 

i have aa NIB A/F sensor for an 02 tacoma V6 if you need one... let me know i can give you a deal on it

 

OK I have the correct info now- I went back to advance and had the scan done again...Now the only code showing is P1135. I had the guy clear it and the light went off for a second then came back almost right away. I think there may have been two problems and now the rear o2 sensor is fixed there is another issue. I am wanting to resolve this but not sure what could be wrong with that code?? Can anyone offer any suggestions about what that code usually means?? is it the A/F sensor?? Thanks alot for all of the replies....This forum is very helpful for those who dont want to bend over and take it to the dealership.

 

You beat me to it Chris! Check the resistance on the 02 sensor(s) in question with a ohm meter to further diagnose the situation. You should be able to get the specs from the FSM.

 

I found this on the web. It could probably help you out some on the troubleshooting... http://www.parksoffroad.com/tacomamods/maintitems/enginecode/cip1135.pdf