Help clearing codes

http://www.tacomaworld.com/forum/1st-gen-tacomas/194366-how-replace-o2-sensors.html

It shouldn't be too hard. You might want to check the connection before you replace the sensor - it could be the connection, wiring, or sensor itself.

Judging by your lean error codes, I suspect your sensor has been slowly dropping in performance over time as it wore out until it finally threw the P0135.

I think the ECU uses the air flow reading from the MAF combined with the readings from the upstream O2 sensor to determine how to adjust the fuel/air mix for best running of the vehicle. So having one of those sensors go bad is very often the cause of lean mix errors like the ones you started this problem with.

 

So what would I look for if I'm just testing the connector?

 

Obvious breaks or wear in the wires?

If you google, there are also tests you can do with a multi-meter to determine if the O2 sensor is actually bad before you replace it.

I also recommend that you double the number of cold beverages prescribed in that tutorial since you're working in NOLA. Make one of them a huge daquiri for me. Yeah you right-

 

Check for exhaust leaks first, check the upstream sensor (very accessible from underneath) if you have a multi-meter check the sensors resistance i think it should be between 10-16 ohms to function correctly. Sometimes cleaning the sensor off will help.

 

I would agree with checking for exhaust leaks if this was to address a P0420 - but I don't think an exhaust leak can cause a P1135.

Checking the sensor's resistance is definitely a good idea.

However, I suspect that because this is the sensor heater circuit that is bad, he will end up replacing that O2 sensor.

Make sure you buy an OEM Denso sensor to replace it with. Rockauto is usually a good place to find the OEM stuff cheap. I think it's only a matter of unplugging the sensor and removing two 10mm nuts to swap it out.

 

yeah it's two highly rusted 10mm bolts and a standard toyota connector. Make sure if your going to pull this sensor that you start saturating the bolts a day or two before so you don't mar the nuts or break the bolts off.

 

...or an air fuel ratio sensor that is stuck at .66v like was the case for me. Cured my P0171.

 

Do you know what the readings for the AF sensor and downstream O2 sensor should be?

I'm curious because I just replaced the upstream and downstream sensors and I'm watching them on my Ultra guage. I see the upstream usually stays around 1.00v and the downstream is kind all over the place between .400v-.800v.

Just wondering if these are normal outputs for a system that is running properly.

 

Here's my o2 sensor. Doesn't appear to have anything messed up with wiring anything like that

 

Unclip it and check it's resistance, only way to know for sure. Takes literally 15 seconds.

 

Where do I grab?

 

Here is a good explanation, i had a bitch of a time figuring it out years ago.
http://www.tacomaworld.com/forum/1st-gen-tacomas/194366-how-replace-o2-sensors.html

 

I should mention, all the clips are the same but you need to wedge a flat head in the hole where you think you would press and pull it out of the retaining clip.