Perfect, thanks.

George

 

Ok so all O2 sensors replaced. I have to know...if after market O2's are any good. Store bought should work but i keep seeing direct fit and the ones I bought is meant for my model but does not say direct fit. No codes...but if they are not working will they spring one??? but same monitors are still present. HTR EVAP.

 

The aftermarket question is a loaded one because there are crappy quality options as well as the OEM version in many cases. When I did a Toyota clutch replacement some years ago I found out that Asin made the OEM version, got the equivalent part number and paid 50% of Toyota prices for the same clutch plate. The replacement has 125k perfect miles on it and it’s “after market”. Once you pick a quality part then you need to match the type (O2 vs wideband) and the wire count. A direct replacement label usually means this plus the correct connector, for plug and play. If not then you may have to do some wire splicing. I have found that Rockauto has a very good part number match track record then sometimes I use Amazon customer ratings if I’m not familiar with a quality pick on that part. Rockauto also has good pictures to match connectors, location etc.

To confirm proper O2 circuit operation:

Any codes or pending codes?
Verify proper switching on a live graph.
Verify proper response by forcing rich then lean on a live graph.
Verify proper heater circuit power.
Verify proper signal ground and high side bias signal and wiring.

Let me know if you need any help with any of this?

George

 

In rereading this article I thought that I could do a better job clarifying some of the sensor technology differences so I edited the text in the original post for clarity and accuracy.

At a later date I intend to pull some pictures and measurements together and get more specific about testing sensors and their wiring.

George

 

Making it a sticky and closing thread