|
| Search | Car Forums | Gallery | Articles | Helper | Air Dried Fresh Beef Dog Food | IgorSushko.com | Corporate |
|
#1
07-30-2003, 02:11 PM
|
|||
|
|||
|
evap system
i have a 1999 suburban 40,000 mi.and 3 times or so ive had it come up with trouble code PO440 evap emission vaccum leak somewhere replaced gas cap with new from dealer. my question i know this is a very complex system but outide if inspecting the lines for breakage where should i start i also notice that on the charcoal canister there are two lines connected they clip on but one does not look secure and it conned=cts to the purge valve. im very sorry for this long post sometimes im long winded i appreciate any imput... thanks
|
|
#2
08-01-2003, 12:36 PM
|
||||
|
||||
|
Evap Codes
A P0440 code is considered a large leak in the EVAP system. Most times it is caused by a loose gas cap.
There have to be certain perameters that are met for the PCM to run the EVAP tests. Check all you lines and fittings and make sure they are secure. Don't beat me up for my next comment......... Your GM dealer has a tool that will pressurize the EVAP system and fill it with smoke to make the leak easier to find. You can always pay for the diagnosis of your problem and then fix it yourself. Some of your EVAP problems are difficult to diagnos, but a large leak should be fairly easy to find.
__________________
Why do you never have enough time or money to do the job right the first time, but enough time and money to do it again? Got all the certifications 25 years ASE Certified Master Technician GM WCT Yea..I work at a DEALERSHIP....got a problem with that? Want to diagnose cars like the Pros? FOR SALE: OTC Perception 2 channel Labscope (badged as a Matco Reality) This is my personal labscope that I use to diagnose waveforms, like new, comes with leads and training video PM Me for details
|
|
#5
08-04-2003, 07:37 AM
|
||||
|
||||
|
It is a possibility.....Have seen a FTP cause a P0440 once or twice ( 1 was leaking)
Before you go and drop the tank to replace it, eliminate the possibility of a leak first.
__________________
Why do you never have enough time or money to do the job right the first time, but enough time and money to do it again? Got all the certifications 25 years ASE Certified Master Technician GM WCT Yea..I work at a DEALERSHIP....got a problem with that? Want to diagnose cars like the Pros? FOR SALE: OTC Perception 2 channel Labscope (badged as a Matco Reality) This is my personal labscope that I use to diagnose waveforms, like new, comes with leads and training video PM Me for details
|
|
#6
08-04-2003, 01:19 PM
|
|||
|
|||
|
ok the only reason i thought that was because the check engine light has come on for po440 and gone off while driving later that week if i had a leak i would think the light could not go off on its own.
|
|
#7
08-05-2003, 08:26 AM
|
||||
|
||||
|
If the light went back off, that means the Evap test ran and passed....could it be possible that you left the gas cap loose and filled your truck up again sometime between when the light came on the first time then went off?
On some trouble codes, the light will turn off if the PCM runs the test and the system passes. There will still be a code stored in history along with some freezeframe and failure records to help with diagnosis.
__________________
Why do you never have enough time or money to do the job right the first time, but enough time and money to do it again? Got all the certifications 25 years ASE Certified Master Technician GM WCT Yea..I work at a DEALERSHIP....got a problem with that? Want to diagnose cars like the Pros? FOR SALE: OTC Perception 2 channel Labscope (badged as a Matco Reality) This is my personal labscope that I use to diagnose waveforms, like new, comes with leads and training video PM Me for details
|
|
#9
08-05-2003, 01:10 PM
|
|||
|
|||
|
i just was looking at vent valve for canister in a diagram and noticed it has a plug in to it. i have a plug hanging underneath my hood in engine compartment guess where it plugs into? canister vent valve... somebody unplugged it maybe when i had alarm put in thank you for help ill see how i do now
|
|
#10
08-05-2003, 06:48 PM
|
||||
|
||||
Excellent find
This would explain your leak....the PCM couldn't close the vent valve.
__________________
Why do you never have enough time or money to do the job right the first time, but enough time and money to do it again? Got all the certifications 25 years ASE Certified Master Technician GM WCT Yea..I work at a DEALERSHIP....got a problem with that? Want to diagnose cars like the Pros? FOR SALE: OTC Perception 2 channel Labscope (badged as a Matco Reality) This is my personal labscope that I use to diagnose waveforms, like new, comes with leads and training video PM Me for details
|
|
#12
08-06-2003, 07:14 AM
|
||||
|
||||
|
Glad I could help
__________________
Why do you never have enough time or money to do the job right the first time, but enough time and money to do it again? Got all the certifications 25 years ASE Certified Master Technician GM WCT Yea..I work at a DEALERSHIP....got a problem with that? Want to diagnose cars like the Pros? FOR SALE: OTC Perception 2 channel Labscope (badged as a Matco Reality) This is my personal labscope that I use to diagnose waveforms, like new, comes with leads and training video PM Me for details
|
|
 |
POST REPLY TO THIS THREAD |
 |
|
|
