O2: what do it do? (O2 delete?)
09-13-2014, 08:16 PM
#1
Registered
Thread Starter
Join Date: May 2011
Posts: 66
Likes: 0
Received 0 Likes
on
0 Posts
O2: what do it do? (O2 delete?)
So dumb question, but with my de-cat causing O2 CEL is there any reason to even have a downstream O2 sensor? I'm gonna mask the code anyway, so can the upstream act solo, and the downstream be essentially deleted without causing the car to limp? I suspect my downstream unit is toast, so if I can just unplug it without ill effect I'll do so.
09-13-2014, 08:18 PM
#2
Registered
iTrader: (2)
Join Date: Oct 2007
Location: Pacific Northwest
Posts: 16,684
Likes: 0
Received 239 Likes
on
109 Posts
The rear O2 has some minor effect on close loop fuel accuracy when the car is in a stable cruise, and it can be used to pull the AFRs back in line if the front O2 were to start sending false signals to the ECU.
Otherwise, no it isn't critical at all, and can be unplugged and removed. They usually fail fast on catless midpipes.
Otherwise, no it isn't critical at all, and can be unplugged and removed. They usually fail fast on catless midpipes.
09-13-2014, 08:25 PM
#3
You gonna eat that?
iTrader: (1)
The rear O2 has some minor effect on close loop fuel accuracy when the car is in a stable cruise, and it can be used to pull the AFRs back in line if the front O2 were to start sending false signals to the ECU.
Otherwise, no it isn't critical at all, and can be unplugged and removed. They usually fail fast on catless midpipes.
Otherwise, no it isn't critical at all, and can be unplugged and removed. They usually fail fast on catless midpipes.
How can one tell when it doesn't work anymore?
09-13-2014, 08:27 PM
#4
Registered
iTrader: (2)
Join Date: Oct 2007
Location: Pacific Northwest
Posts: 16,684
Likes: 0
Received 239 Likes
on
109 Posts
There are 9 different codes that are triggered from the rear O2 sensor, i think 4 of them are direct O2 sensor failure codes, with at least 2 more possible with a rear sensor failure. P0420 appearing generally means that it is working, but not explicitly. It's possible that it is just in the progress of failing, and failing the cat efficiency test without failing any of the others yet. There isn't a predefined pattern of exactly how they will fail every time. I've seen a few different ways, and I doubt I've seen them all.
It's most easily identified in the mode6 test data though, as it will fail any one of the tests that are run, even before the ECU decides to use those failures to throw one of the failure codes.
It's most easily identified in the mode6 test data though, as it will fail any one of the tests that are run, even before the ECU decides to use those failures to throw one of the failure codes.
09-13-2014, 08:36 PM
#5
You gonna eat that?
iTrader: (1)
Thank you.