Hi I know this might be a dumb question but how does the ecu read the results of the new 02 sensors installed there is no lead that goes to wiring harness.
And I am trying to get oxygen sensor monitor to come off my scanner i have three codes.
With a 99 you are allowed two inc monitors
If I get off just one more i will pass inspection,and I cannot renew registration until I get inspected .so my question is how does the computer know that you replaced the o2 sensors.
The computer is tellin me the up streams are bad i bought them but I see no wire at all going to a harness that ecu would get info from .
They just clip into each other both up streams in front
Someone please help asap.thank you jeffre

 

Clip into each other.....no
Little tabs at back of block (can see the from to of engine) holds the harness

 

I can see on my discovery that they plugged right into each other i just want to know hoe does the ecu know u changed out your upstream o2 sensors

 

Basically the ECU will get a new set of signal pulses which will most likely differ from the originals. Each sensor signalling is recorded as STFT--short term fuel trims.
These are then computed as LTFT's-Long term fuel trims which finally set the fueling.
Operating the vehicle & going through drive cycles the ECU will 'learn" the new signalling and compute the LTFT's.

Fuel trim can be a valuable diagnostic tool - Eastern Manufacturing

T/V

 

I'll give it a shot thank you so you know definitely there are no wires in between buth up streams
That go to a ecu by harness or anything
They just hook up to each other

 

Yes they just hook up to each other there is no wire or lead that looks like it hooks up to the ecu.if not how can a scanned readt monitor ok come up to pass an inspection .pla replynasaj

 

Post photos. They do not clip into each other. If you have andriod tabket or phone, get a bluetooth OBD II reader and the torque app. You will be able to see the real time values from the O2 sensors.