I'm getting P0140 on my Blazer and I found this very helpful diagnostic procedure to find the cause of my problem
https://blazerforum.com/forum/2nd-ge...or-help-61977/

I have already replaced the sensor.

I followed the steps #5 -> #9 -> #10 -> #11 ->#15.
Connector from the car looks OK, no corrosion and cables are OK.
But it doesn't fully engage to the bottom and the lock clip doesn't reach all the way as you can see on the picture below. Could this lead to the error code?

I will order a new connector and hope that it will cure the problem.

 

Try putting a tiny bit of dielectric grease or silicone lube on the rubber seal. Sometimes, that helps the connectors go together easier.

 

Thanks for the tip Tom, but it didn't do any difference. It feels like there is something in the bottom that stops the connector to go all in.
Bought the car a year ago and that connector was loose as on the picture when I changed the sensor. So it has been more exposed to road grime and salt. The black part is facing forward and get spray from the right front wheel.
Salt and road grime acts like cement and destroys stuff very soon.

Where should that plastic plug go to place the connector assembly to proper way, hopefully it will be more protected then.


Thanks

 

I think it just fits into a hole in the frame. You should be able to buy that connector as a "pigtail" and splice it to your harness.

 

Yes I have ordered one, it will be here in a week. I'm in Sweden, car is sold new here and is an export model. Some "special" stuff on it. But got to fix this before the inspection in June

 

I have now changed the connector and the values I get on the sensor is moving around but I suspect that they are not really OK.
They vary between 0.460 down to 0.420 while driving. I guess that they should have a larger span. Drove it about 20 miles and the light didn't come on but I had one pending P0140 when I got home.

Any one who knows what the proper values should be?


Thanks

 

Is this the post cat sensor? If so then it should hover around 0.5 - 0.7v and not switch like the pre cat O2 sensors.


George

 

Yes George, it is the post cat sensor.

I have to go over the diagnostic once more to see what could be wrong.

Thanks

 

If you come up with no solution let me know and I can jump in to help if you would like.


George

 

Thanks George, anyway I get better readings now with the new connector. The sensor itself is just a few months old. Must be some cable issue upstream from the connector.

I will not have time to check it further in a few weeks but I'll reprot back after I done the diagnostics.


Thanks