Frez Posted November 21, 2011 Share Posted November 21, 2011 I like to fix things myself.....most of the time I can. My daughters car is a 2003 Chevy Cavalier with 91,000 miles. A few weeks ago the check engine light came on with a code of P0456 (Small Evap Leak). Here is what I've done so far to try correcting it. 1. New OEM Gas cap 2. Replaced Canister vent solenoid at the rear and checked all wires for broken or damage. 3. Did a smoke test on it with a mechanic friend. Could NOT find any leaks at all. 4. Reset the check engine light 3 times now after doing each step to only have the light return on after 40 to 60 miles of driving in the car. I'm really stumped and not sure what I should try next. Any help would be greatly appreciated! Thank you and I look forward to correcting this problem. I hate being stumped! What are my final options? 1. replace purge solenoid at front? 2. Could it be the engines PCM (Computer)? 3. Vapor Charcoal Canister? 4. Gas filler tube to the tank? 5. What about the Fuel Tank Pressure Sensor? Like I said...there were NO visible leaks when we smoke tested it. We did this test numerous times! Link to comment Share on other sites More sharing options...
BuffaloBill Posted November 21, 2011 Share Posted November 21, 2011 Take the car out to an old country road. Rip the radio out, take the tires and then burn it. You can buy another with the insurance check. Clearly, I have no idea what to do Link to comment Share on other sites More sharing options...
Fan in San Diego Posted November 21, 2011 Share Posted November 21, 2011 Take it to the dealer to be fixed. A man has got to know his limitations. Link to comment Share on other sites More sharing options...
Frez Posted November 21, 2011 Author Share Posted November 21, 2011 Take it to the dealer to be fixed. A man has got to know his limitations. The fix is easy if you know exactly what to replace. I refuse to give the stealer my hard earned money if I can repair it myself. Link to comment Share on other sites More sharing options...
Fezmid Posted November 22, 2011 Share Posted November 22, 2011 Did you make sure you tightened the gas cap so that it clicks a few times? When my check engine light turned on years ago, I was told to do that and wait a few days. Sure enough, the light went out and hasn't been back on since. Apparently the sensor takes a while to "reset" itself or something... Link to comment Share on other sites More sharing options...
Jim in Anchorage Posted November 22, 2011 Share Posted November 22, 2011 You've done far more then I would have. It's not going to hurt anything. Link to comment Share on other sites More sharing options...
/dev/null Posted November 22, 2011 Share Posted November 22, 2011 Take it to the dealer to be fixed. A man has got to know his limitations. The fix is easy if you know exactly what to replace. Can't fix the problem if you don't know what's wrong. Spend a hundred or so at the dealership for a diagnostic. I had a problem with my '98 Cavalier that multiple mechanics couldn't fix. One of them told me to take it to a dealership because they have better diagnostic tools. Took it to a Chevy dealership and they couldn't figure out what's wrong either. Ended up taking it to a Cadlillac dealership to fix the problem with my Chevy Link to comment Share on other sites More sharing options...
Dave_In_Norfolk Posted November 22, 2011 Share Posted November 22, 2011 I like to fix things myself.....most of the time I can. My daughters car is a 2003 Chevy Cavalier with 91,000 miles. A few weeks ago the check engine light came on with a code of P0456 (Small Evap Leak). Here is what I've done so far to tr Thank you and I look forward to correcting this problem. I hate being stumped! What are my final options? 1. replace purge solenoid at front? 2. Could it be the engines PCM (Computer)? 3. Vapor Charcoal Canister? 4. Gas filler tube to the tank? 5. What about the Fuel Tank Pressure Sensor? Like I said...there were NO visible leaks when we smoke tested it. We did this test numerous times! A vacuum leak from a hose? Is there a PCV valve? Link to comment Share on other sites More sharing options...
Cynical Posted November 22, 2011 Share Posted November 22, 2011 A vacuum leak from a hose? Is there a PCV valve? "A" for effort, but wrong system. IIRC, the EVAP system the OP is talking about deals with the fuel vapors in the fuel tank. Link to comment Share on other sites More sharing options...
boyst Posted November 22, 2011 Share Posted November 22, 2011 Frez, it's lupus. Always Lupus. I had a problem with my '98 Cavalier that multiple mechanics couldn't fix. One of them told me to take it to a dealership because they have better diagnostic tools. Took it to a Chevy dealership and they couldn't figure out what's wrong either. Ended up taking it to a Cadlillac dealership to fix the problem with my Chevy My 98 Cavy is kicking ass. 126k on it, gramps bought it brand new in the summer of 99 for me for a steal. It has had not one major issue, nor small. The AC finally went out last year, but other then that it's cool. I have only floored it a dozen times, and had to jump a median - literally, slamming the air damn in to the road but no damage. (Gramps was pretty much on death bed and I got the call to go - I went.) Link to comment Share on other sites More sharing options...
Frez Posted November 22, 2011 Author Share Posted November 22, 2011 Did you make sure you tightened the gas cap so that it clicks a few times? When my check engine light turned on years ago, I was told to do that and wait a few days. Sure enough, the light went out and hasn't been back on since. Apparently the sensor takes a while to "reset" itself or something... Not only is the gas cap tight, but I replaced the old with a nice new OEM cap. thanks Can't fix the problem if you don't know what's wrong. Spend a hundred or so at the dealership for a diagnostic. I had a problem with my '98 Cavalier that multiple mechanics couldn't fix. One of them told me to take it to a dealership because they have better diagnostic tools. Took it to a Chevy dealership and they couldn't figure out what's wrong either. Ended up taking it to a Cadlillac dealership to fix the problem with my Chevy I have access to most of the diagnostic tools where I work. I'm friends with a few good mechanics too. Thing is they are not chevy certified nor do they work on these common problems all the time. We have a smoke machine that will tell you where the leak is coming from and we tried that but didn't see any leaks in the system at all. I think I have it narrowed down to the wire harness at the vent solenoid at the rear of the car. Thanks for the reply Link to comment Share on other sites More sharing options...
Fezmid Posted November 22, 2011 Share Posted November 22, 2011 Not only is the gas cap tight, but I replaced the old with a nice new OEM cap. You missed the second part of my response -- have you waited a few days to see if the light goes off? Link to comment Share on other sites More sharing options...
Frez Posted November 22, 2011 Author Share Posted November 22, 2011 (edited) You missed the second part of my response -- have you waited a few days to see if the light goes off? Fez, I replaced the cap with a new OEM and even had the code reset with automotive scanner. The check engine light still came back on. I wish it was just the gas cap this time. thanks Edited November 22, 2011 by Frez Link to comment Share on other sites More sharing options...
Cynical Posted November 22, 2011 Share Posted November 22, 2011 You missed the second part of my response -- have you waited a few days to see if the light goes off? You missed step 4 in his initial post: "4. Reset the check engine light 3 times now after doing each step to only have the light return on after 40 to 60 miles of driving in the car." That means he's cleared the code from the cars PCM memory which in turns out the light. The light keeps coming back on because the code keeps being set. The code keeps being set because the problem hasn't been fixed. Link to comment Share on other sites More sharing options...
Fezmid Posted November 22, 2011 Share Posted November 22, 2011 You missed step 4 in his initial post: "4. Reset the check engine light 3 times now after doing each step to only have the light return on after 40 to 60 miles of driving in the car." That means he's cleared the code from the cars PCM memory which in turns out the light. The light keeps coming back on because the code keeps being set. The code keeps being set because the problem hasn't been fixed. Ahh, you're right, I didn't see that the light was being reset. My mistake! Link to comment Share on other sites More sharing options...
unbillievable Posted November 23, 2011 Share Posted November 23, 2011 The clear answer is to repeat step #4 everey 40 to 60 miles. Link to comment Share on other sites More sharing options...
MarkyMannn Posted November 23, 2011 Share Posted November 23, 2011 Here is some real help. Purge valve Link to comment Share on other sites More sharing options...
/dev/null Posted November 23, 2011 Share Posted November 23, 2011 My 98 Cavy is kicking ass. My 98 Cav has been kicking ass too, but.... The AC Condenser needs to be replaced. This time of year I can live with it, but once it starts getting hot... The cost of repairs vs the resale value doesn't really merit fixing it I love that car too One of these days I'll have to figure out whether it makes more financial sense to trade into the dealer the car for the pittance it will take on the market or to donate it to the Save The Whales/Vets/Environment/Retards/Gays/Elderly/ElderlayGayWhaleHumpingVetHippies for the tax break Link to comment Share on other sites More sharing options...
Nanker Posted November 23, 2011 Share Posted November 23, 2011 Did you check the transmission coolant lines? Take it to Pep Boys for a diagnosis. /suggestions. Link to comment Share on other sites More sharing options...
Frez Posted November 23, 2011 Author Share Posted November 23, 2011 Here is some real help. Purge valve I'm replacing the purge valve next. If that don't do it I will double check the wire harness at the rear that goes to the vent solenoid valve. Thanks Did you check the transmission coolant lines? Take it to Pep Boys for a diagnosis. /suggestions. Thank you but... The tranny lines have nothing to do with EVAP code. Link to comment Share on other sites More sharing options...
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