no O2 voltage in data tables when V2 is connected to PCM but there in log on playback

[Eric]

Hi everyone had this thread in gen 3 but might be better here , just want to know if this is normal , when i select O2S11 and O2S21 voltages along with the short term feul trims that come with these PIDs i get no voltages or feul trim % in the live data table but if i save the log and play it back there they are , the heated HO2S11 and HO2S21 voltages are in the live data table , by the way what is the difference between heated and not , my truck is a 2000 silverado 4.8l and i noticed that it did it also when connected to my friends 98 5.7 vortec , thanks in advance Eric

[joecar]

Hi Eric,

I would ignore the O2S11/21 pids, they have multi-functioned values (in the PIDs tab, on those pids do rightclick->More info).

I prefer the HO2S11/21 pids instead, these are the raw front NBO2 voltages.

Your Vortec probably has heated O2 sensors ("heated" seems to be an OBD-2 requirement).

Heated NBO2: 3 or 4 wire, contains integral heating element to bring sensor up to temperature sooner.
Unheaded NBO2: 1 or 2 wire, contains no heater, relies on exhaust gas temperature to be sufficient to heat sensor.

$0.02

[Eric]

Tahnks Joe , but why are the voltages there in the log but not in live data , ok i think i just got it ,my 2000 silverado and my friends 98 5.7 vortec have the heated NB02s so when in live data i get nothing from the unheated NB02 and when i play a log back and if if i have logged both heated and non heated pids the voltage from my heated NB02s will be sent to the non heated NB02 pids , is this it , so it i want to log short term feul trims i have to select the non heated NB02 pids and they will be in the log , it makes sence that the scan tool will not give you the same value in two places in the data table , is all this making sence and is it correct , so non heated NB02 pids along with short term feul trims will not show up as live data but will be logged , are you still on , thanks Joe Eric

[Eric]

Ok Joe just realized that i can seperately in both cases my truck and my friends log seperately short term feul trims and this is making sence to me now , by having the heated NB02 installed > this pid is just sendind the voltage it reads when logged to the non heated pid , why does it let me sellect these pids if they are not really availible , thanks Joe Eric