*** Restricting New Posts to SD Premium Members ONLY *** (09 May 2025)
Just made a new account? Can't post? Click above.
Oxygen sensor functioning
- cyrus.nk
-
Topic Author
- Offline
- Senior Member
-
- Posts: 60
- Thank you received: 0
Please Log in or Create an account to join the conversation.
- Noah
-
- Offline
- Moderator
-
- Give code definitions with numbers!
- Posts: 4907
- Thank you received: 1097
This is also true if the catalytic converter is no longer functioning.
"Ground cannot be checked with a 10mm socket"
Please Log in or Create an account to join the conversation.
- cyrus.nk
-
Topic Author
- Offline
- Senior Member
-
- Posts: 60
- Thank you received: 0
Please Log in or Create an account to join the conversation.
- Tyler
-
- Offline
- Moderator
-
- Full time HACK since 2012
- Posts: 6039
- Thank you received: 1518
cyrus.nk wrote: So if catalytic converter is removed,will the car set p0420 ?
Absolutely. Most catalyst monitors will pick up on that VERY quickly.
Please Log in or Create an account to join the conversation.
- cyrus.nk
-
Topic Author
- Offline
- Senior Member
-
- Posts: 60
- Thank you received: 0
Please Log in or Create an account to join the conversation.
- Noah
-
- Offline
- Moderator
-
- Give code definitions with numbers!
- Posts: 4907
- Thank you received: 1097
"Ground cannot be checked with a 10mm socket"
Please Log in or Create an account to join the conversation.
- Andy.MacFadyen
-
- Offline
- Moderator
-
- Posts: 3353
- Thank you received: 1036
" We're trying to plug a hole in the universe, what are you doing ?. "
(Walter Bishop Fringe TV show)
Please Log in or Create an account to join the conversation.
- Tyler
-
- Offline
- Moderator
-
- Full time HACK since 2012
- Posts: 6039
- Thank you received: 1518
Please Log in or Create an account to join the conversation.
- cyrus.nk
-
Topic Author
- Offline
- Senior Member
-
- Posts: 60
- Thank you received: 0
Please Log in or Create an account to join the conversation.
- rockp2
-
- Offline
- Elite Member
-
- Posts: 167
- Thank you received: 40

Please Log in or Create an account to join the conversation.
- Tyler
-
- Offline
- Moderator
-
- Full time HACK since 2012
- Posts: 6039
- Thank you received: 1518
Short answer, some makes/models DO use the downstream O2 for some degree of fuel control. It's all about 'fine tuning' catalyst performance, as I understand it, and controlling how much oxygen the catalyst is storing at a given time. Any more, just knowing how the catalyst is performing isn't good enough. :blink: The OE now wants to make sure the catalyst is performing at it's best across a wide range of conditions.
In my experience, IF a vehicle uses downstream fuel trims, then there's usually some kind of data PID to go along with it. I've also noticed that the 'weight' of the downstream fuel trim is very light compared to the main short term/long term trims. Most models I've seen won't let the trims run away with a downstream O2 problem, but there are exceptions of course:
Please Log in or Create an account to join the conversation.
- rockp2
-
- Offline
- Elite Member
-
- Posts: 167
- Thank you received: 40

Please Log in or Create an account to join the conversation.