Vette failed emissions
Thread Starter
Burning Brakes
Joined: May 2006
Posts: 774
Likes: 1
From: Round Rock Texas
Vette failed emissions
I am posting a pic of the emissions fail to see if anyone can interpret this. I have replaced the MAF sensor and both pre-cat O2 sensors. Reset and the check engine light went off. Took in for inspection and failed and then the light came back on as I left.
Hope you can help.
Thanks.
Hope you can help.
Thanks.
Thread Starter
Burning Brakes
Joined: May 2006
Posts: 774
Likes: 1
From: Round Rock Texas
Tech Contributor
Joined: Oct 1999
Posts: 41,037
Likes: 9,799
From: Charlotte, NC (formerly Endicott, NY)
What made you decide to replace the MAF and the O2 sensors? So what codes are present on the car now? You have to know what the codes are if you hope to do any diagnosis. That sheet of paper is worthless from a diagnostic standpoint other than telling you a couple of systems weren't ready when the test was run.
Bill
Bill
Thread Starter
Burning Brakes
Joined: May 2006
Posts: 774
Likes: 1
From: Round Rock Texas
What made you decide to replace the MAF and the O2 sensors? So what codes are present on the car now? You have to know what the codes are if you hope to do any diagnosis. That sheet of paper is worthless from a diagnostic standpoint other than telling you a couple of systems weren't ready when the test was run.
Bill
Bill
Thanks.
Thread Starter
Burning Brakes
Joined: May 2006
Posts: 774
Likes: 1
From: Round Rock Texas
What made you decide to replace the MAF and the O2 sensors? So what codes are present on the car now? You have to know what the codes are if you hope to do any diagnosis. That sheet of paper is worthless from a diagnostic standpoint other than telling you a couple of systems weren't ready when the test was run.
Bill
Bill
Thanks.
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Tech Contributor
Joined: Oct 1999
Posts: 41,037
Likes: 9,799
From: Charlotte, NC (formerly Endicott, NY)
It had a P-158 and 160 co showing. Looking at all the stuff all over the internet most stated it was usually the pre-cat O2 sensor out. I had it scanned and it showed could be MAF or O2 sensor. So...now I am back to the drawing board. I have been reluctant to take it back to the dealership because they will charge me an arm and a leg and was hoping to do it myself.
Thanks.
Thanks.
Take one of the two sensors you removed and use it to replace the passenger side post cat sensor and see what happens. While doing that check the wiring to the rear sensor and see if it is shorted to the exhaust or frame.
See Attached Diagnostic Procedures
Bill
Last edited by Bill Dearborn; Mar 24, 2012 at 10:41 PM.
Drifting
Joined: Feb 2012
Posts: 1,796
Likes: 37
From: skiatook oklahoma
post-cat... i thought you got that fixed... you did pre-cats??
http://forums.corvetteforum.com/c6-t...post1580331542
http://forums.corvetteforum.com/c6-t...post1580331542
Race Director
Joined: Mar 2005
Posts: 10,399
Likes: 25
From: Austin Texas
Passing requires a certain number of "drive cycles" between any changes to the computer. If you re-set any codes you have to cycle the computer xx times to get a new base reading.
2008? Why does the test show a 6.0 L engine? Wrong inputs could cause bad readings.
2008? Why does the test show a 6.0 L engine? Wrong inputs could cause bad readings.
Instructor
Joined: Jan 2007
Posts: 157
Likes: 0
From: The Hills TX
As stated above, this means that you have not driven it enough cycles/miles. Even if you unhook the battery, it will take several cycles and a few miles before it will pass.
I had this problem on my LX470. Disconnected the battery to replace the drivers side headlight and only used it to go to the store. Then the next day drove it to inspection station. Did not pass. (Just like yours, my Catalyst, etc was NOT READY).
They asked me if I had disconnected the battery recently and I said yes.They then told me to drive it about 50 mi and several off/on and bring it back. It passed then.
Good Luck!
Thread Starter
Burning Brakes
Joined: May 2006
Posts: 774
Likes: 1
From: Round Rock Texas
Your sheet shows the Catalyst, Evap, and O2 NOT READY!
As stated above, this means that you have not driven it enough cycles/miles. Even if you unhook the battery, it will take several cycles and a few miles before it will pass.
I had this problem on my LX470. Disconnected the battery to replace the drivers side headlight and only used it to go to the store. Then the next day drove it to inspection station. Did not pass. (Just like yours, my Catalyst, etc was NOT READY).
They asked me if I had disconnected the battery recently and I said yes.They then told me to drive it about 50 mi and several off/on and bring it back. It passed then.
Good Luck!
As stated above, this means that you have not driven it enough cycles/miles. Even if you unhook the battery, it will take several cycles and a few miles before it will pass.
I had this problem on my LX470. Disconnected the battery to replace the drivers side headlight and only used it to go to the store. Then the next day drove it to inspection station. Did not pass. (Just like yours, my Catalyst, etc was NOT READY).
They asked me if I had disconnected the battery recently and I said yes.They then told me to drive it about 50 mi and several off/on and bring it back. It passed then.
Good Luck!
Thanks everyone.
Drifting
Joined: Feb 2012
Posts: 1,796
Likes: 37
From: skiatook oklahoma
Marz... you get a good inspection yet?
someone asked almost your identical question about 'not ready'.
see link, see post #6 , might be helpful
http://forums.corvetteforum.com/c6-t...ive-cycle.html
someone asked almost your identical question about 'not ready'.
see link, see post #6 , might be helpful
http://forums.corvetteforum.com/c6-t...ive-cycle.html