I know this video is old but that's not how the downstream O2 sensor operates. You actually want to see the downstream stay steady. The upstream O2 sensor jumps between 0.1V and 0.9V to show the oxygen level in the exhaust caused by the increase and decrease of fuel commanded by the PCM to the injectors. The downstream O2 sensor reads the oxygen to show the efficiency of the catalytic converter. An efficient CAT will convert the oxygen so that very little oxygen exits the CAT. Because the oxygen level is very minimal, the downstream O2 sensor should be a steady reading. If the CAT were bad, however, you would not have the oxygen conversion taking place and the downstream O2 sensor will begin to look like the upstream O2 sensor. The downstream will normally jump up and down like the upstream while the vehicle is still trying to reach operating temperature, but once heated up, it should develop a constant signal. If it continues to jump up and down, this would be an indication of a bad CAT...or an exhaust leak, so a system should always be checked for an exhaust leak before condemning the CAT. Just an FYI.
i think what the video says is that the downstream one is very low value (0.06V), indicating there is too much oxygen, which implies there is a leak in the exhaust.
my car has a very obvious exhaust leak at a makeshift coupler, carbon deposits coming out. but i passed emissions and my gas mileage is what its supposed to get. pray tell
Toyota Honda I'll have to look Alot of people ask that so I will get back to you on that. As long as you buy one with live data capabilities you can't go wrong!
Benjamin Brown so both the sensors are reading the same number? And if so this is with the car fully warmed up and it doesn't fluctuate holding a steady rev?
I just bought the same scanner. As soon as i crank the car the screen goes blank back light. Works fine reads codes with key on engine off. Yes its supposed to read live data
I know this video is old but that's not how the downstream O2 sensor operates. You actually want to see the downstream stay steady. The upstream O2 sensor jumps between 0.1V and 0.9V to show the oxygen level in the exhaust caused by the increase and decrease of fuel commanded by the PCM to the injectors. The downstream O2 sensor reads the oxygen to show the efficiency of the catalytic converter. An efficient CAT will convert the oxygen so that very little oxygen exits the CAT. Because the oxygen level is very minimal, the downstream O2 sensor should be a steady reading. If the CAT were bad, however, you would not have the oxygen conversion taking place and the downstream O2 sensor will begin to look like the upstream O2 sensor. The downstream will normally jump up and down like the upstream while the vehicle is still trying to reach operating temperature, but once heated up, it should develop a constant signal. If it continues to jump up and down, this would be an indication of a bad CAT...or an exhaust leak, so a system should always be checked for an exhaust leak before condemning the CAT. Just an FYI.
i think what the video says is that the downstream one is very low value (0.06V), indicating there is too much oxygen, which implies there is a leak in the exhaust.
Teaching something!! Don't forget that part
Thanks bro you make my day 😀😀😀
my car has a very obvious exhaust leak at a makeshift coupler, carbon deposits coming out.
but i passed emissions and my gas mileage is what its supposed to get.
pray tell
Greatly appreciate what is your scanner model numbers? Thanks
Toyota Honda I'll have to look Alot of people ask that so I will get back to you on that. As long as you buy one with live data capabilities you can't go wrong!
Isn't that the o2 sensor after the cat? It should be lower number I think
Will this type of exhuast leak cause the car to have to much fuel?
yes it can
You're right
On my 98 trans am my 02 sensor read .445 on bank 1 and bank 2 the front sensor
Benjamin Brown so both the sensors are reading the same number? And if so this is with the car fully warmed up and it doesn't fluctuate holding a steady rev?
get a welder even a flux core welder and save lotta money in long run
I just bought the same scanner. As soon as i crank the car the screen goes blank back light. Works fine reads codes with key on engine off. Yes its supposed to read live data
Yawn