C3 guy with C5 PCM Issue / Emissions Problem
Thread Starter
Drifting
Joined: Mar 2004
Posts: 1,449
Likes: 40
From: Panama City Beach, Florida
C3 guy with C5 PCM Issue / Emissions Problem
Hello all,
I have a '97, all stock. Long story short - check engine light on, O2 sensor code, replace them, erase codes, (my mistake) then I had to take it for Emissions test (Illinois) it didn't pass, they rejected it because, the catalyst & evap systems show "not supported" which means the I M readiness test systems don't have enough drive time to do a system check. When you clear the codes like I did it clears the I M system as well.
I got the GM drive cycle info, drive 55 for 3 minutes, decelerate to 20, etc. etc.
So - I've driven all the cycles a couple times over and still the I M systems are not ready so it still won't pass. Can't get a license plate sticker until it passes.
The emissions guy says he thinks the computer needs to be re-flashed -
OR maybe I should buy a new PCM ?
Any ideas ?
Thanks, Frank
I have a '97, all stock. Long story short - check engine light on, O2 sensor code, replace them, erase codes, (my mistake) then I had to take it for Emissions test (Illinois) it didn't pass, they rejected it because, the catalyst & evap systems show "not supported" which means the I M readiness test systems don't have enough drive time to do a system check. When you clear the codes like I did it clears the I M system as well.
I got the GM drive cycle info, drive 55 for 3 minutes, decelerate to 20, etc. etc.
So - I've driven all the cycles a couple times over and still the I M systems are not ready so it still won't pass. Can't get a license plate sticker until it passes.
The emissions guy says he thinks the computer needs to be re-flashed -
OR maybe I should buy a new PCM ?
Any ideas ?
Thanks, Frank
Safety Car
Joined: Jul 2010
Posts: 3,951
Likes: 386
From: Chandler AZ
PCM would be expensive!
Can you get a temporary permit to keep driving the car to get the systems ready again?
I changed my oil and reset the oil life monitor same day getting emissions test here in Phoenix area, they told me the same thing, and they offered to do the test they do on OBD 1 or 1995 and older vehicles.
They put my corvette on the dyno rollers and put sniffer pipe on my muffler tips, it passed and saved me the same BS you are going through.
Ask if that is a option in your area.
Can you get a temporary permit to keep driving the car to get the systems ready again?
I changed my oil and reset the oil life monitor same day getting emissions test here in Phoenix area, they told me the same thing, and they offered to do the test they do on OBD 1 or 1995 and older vehicles.
They put my corvette on the dyno rollers and put sniffer pipe on my muffler tips, it passed and saved me the same BS you are going through.
Ask if that is a option in your area.
Last edited by 1999corvettels1; Apr 2, 2018 at 10:45 PM.
Thread Starter
Drifting
Joined: Mar 2004
Posts: 1,449
Likes: 40
From: Panama City Beach, Florida
PCM would be expensive!
Can you get a temporary permit to keep driving the car to get the systems ready again?
I changed my oil and reset the oil life monitor same day getting emissions test here in Phoenix area, they told me the same thing, and they offered to do the test they do on OBD 1 or 1995 and older vehicles.
They put my corvette on the dyno rollers and put sniffer pipe on my muffler tips, it passed and saved me the same BS you are going through.
Ask if that is a option in your area.
Can you get a temporary permit to keep driving the car to get the systems ready again?
I changed my oil and reset the oil life monitor same day getting emissions test here in Phoenix area, they told me the same thing, and they offered to do the test they do on OBD 1 or 1995 and older vehicles.
They put my corvette on the dyno rollers and put sniffer pipe on my muffler tips, it passed and saved me the same BS you are going through.
Ask if that is a option in your area.
I did get a temporary sticker for the plates -
They don't do a sniff test or OBD 1, they discontinued the dyno also so I'm stuck right now -
I can get a PCM on ebay relatively cheap but I've read that the connectors and the connection can be corroded and that could be part of the problems but I don't want to open that can of worms just yet -
Thanks, Frank
Last edited by myoriginal77; Apr 2, 2018 at 11:42 PM. Reason: typo
Safety Car
Joined: Jul 2010
Posts: 3,951
Likes: 386
From: Chandler AZ
I think (could be wrong) replacing the PCM would again reset all the readiness modules.
Go drive the car as much as you can, light to light, freeways, out on country roads, one would think this would help get it ready to be tested.
If you aren't allowed to drive the car except from home, to repair and emissions test place, that makes it tough!
Probably like waiting for water to boil, takes a bit of time.
Go drive the car as much as you can, light to light, freeways, out on country roads, one would think this would help get it ready to be tested.
If you aren't allowed to drive the car except from home, to repair and emissions test place, that makes it tough!
Probably like waiting for water to boil, takes a bit of time.
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Burning Brakes
Joined: Apr 2017
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From: Romeoville, IL
drive drive drive. It may take 50 miles it may take 100 miles. If it doesn't set you have a broader issue.
MY 2k trans am would take 153 miles before it put everything into ready mode for emissions.
MY 2k trans am would take 153 miles before it put everything into ready mode for emissions.
Thread Starter
Drifting
Joined: Mar 2004
Posts: 1,449
Likes: 40
From: Panama City Beach, Florida
Thanks for the replies -
Thats the problem, I have been driving it, probably 600 miles or more - the readiness codes still have not reset.
I did find GM drive cycles online and have tried doing that but with no luck so far -
Thanks again, Frank
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Drifting
Joined: Oct 2002
Posts: 1,773
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From: SoCal
But with "Not Supported" showing up in the scanner, Those will never set to "ready".
Thread Starter
Drifting
Joined: Mar 2004
Posts: 1,449
Likes: 40
From: Panama City Beach, Florida
Are you sure it said "Not Supported", if so, you could drive the car until the wheels fall off and they will never set. Now if it said "Not Ready", then it will take drive cycles to get them to "ready". As to why it says "Not Supported", you have to find out why it thinks that. Either something has been changed in the tune to where you are getting that or something else is wrong. PCM issue possibly.
But with "Not Supported" showing up in the scanner, Those will never set to "ready".
But with "Not Supported" showing up in the scanner, Those will never set to "ready".
Anyhow, I didn't actually "Fail" I was "Rejected." There is a difference here, when rejected you can't get a waiver like you could if it failed.
When I check with my scanner it shows n/a for the catalytic converter, heated catalyst and evaporative system, in the IM readiness mode.
From all I can read on the subject it looks like there could be a tune I'm not aware of. I'm the 3rd owner but I know the previous owner and he says no tune and it passed two years ago while he had it.
Again from the internet it says that it might need to be re-flashed, I'm going to check with a local tuner. It does sound like you mentioned it may be a PCM issue.
Thanks again. Frank