Check engine light - oxygen sensor gen3

[07GTS]

there are some idle airflow trims that prob need to relearn also

 

[lout]

there are some idle airflow trims that prob need to relearn also

this is being done with O2 unplugged to try and determine if engine is actually running lean
or faulty O2 sensor circuit

 

[07GTS]

this is being done with O2 unplugged to try and determine if engine is actually running lean
or faulty O2 sensor circuit

idle airflow trims are just for idle control, the 02's if u unplug them will prob default to a OL richer commanded fuel for safety, if u can read the 02 data close to 0mv is lean, close to 1000mv is rich, if unplugged or wiring issues it can stay at the 450mv without moving showing open circuit issue,

if u had a wideband u could force open loop and see if actual fueling is lean or if 02s are causing false lean but not sure if id trust unplugging them as some ecu will fault where as getting to to go OL just then uses the fueling tables without fault

 

[lout]

Lh O2 was reading 450mv with plus 22% fuel trim
so trying to determine if actually that lean on one bank only
and why ecu added that much fuel if O2 open circuit

 

[07GTS]

Lh O2 was reading 450mv with plus 22% fuel trim
so trying to determine if actually that lean on one bank only
and why ecu added that much fuel if O2 open circuit

is the 02 just flatlining at the 450mv or does it still move when some throttle ?

the fuel trims dont go on for too long and the 22% may be it maxed out so it sits there as the 02 is reading 450mv, if the 02 moved down towards zero then the trims should lower, what the trims want to do is cycle the 02's reading slightly above and below the 450mv so if its added a heap to get it then but it dosnt go further it will stay there still trying to get it to cycle, are u looking at LTFT or STFT ?

 

[lout]

i dont think op is confident to do detailed testing

 

[07GTS]

if u can watch the 02 from dead cold as they always start at the 450mv and soon as the get enough heat they begin to move with the fueling then once they are up to set temp they are reliable the ecu uses them for feedback, if it never moves from the 450 then sounds like its either unplugged or has a wire open circuit on the signal side which would need testing

 

[B-Man]

done another few runs with them unplugged.
its now cleared the idle up and is driving the same as it was with them plugged in. it even gets the error code at the same time.

the last time I put them on the scan tool they basically sat at the 450mv and didn't really move no matter the revs or how long I left it.
they also both are now showing not ready where it was only the left hand one before. not sure what the mechanic done but ther plugs were both pulled up so could be unclipped from above. it could have pulled a wire? I havent touched the sensors since the first post with them showing on the scan tool until unplugging them a few days ago.

seems like it could be a wiring issue then? maybe the plug isn't connecting properly? since I did get continuity along the wire...

think I need to get my own Bluetooth obd2 reader so I can test it over the weekend rather than just scanning the car in my lunch break.

 

[B-Man]

if u can watch the 02 from dead cold as they always start at the 450mv and soon as the get enough heat they begin to move with the fueling then once they are up to set temp they are reliable the ecu uses them for feedback, if it never moves from the 450 then sounds like its either unplugged or has a wire open circuit on the signal side which would need testing

thats what the left one was doing before I took it to a mechanic.... they didnt resolve it.... now both are doing it.....

 

[lout]

unplugged will show not ready and 450mv
but how did it drive
getting your own scan tool with live data will make diagnosing a lot easier