I’m hoping that someone can provide me with some insight into a check engine light issue. For the past 3 months, my check engine light has been turning on. The first time it happened, the garage replaced the EVAP Purge Solinoid (which includes the vapor can purge solinoid and the EVAP canister purge solinoid). Of course, a few months later, the check engine light turned on again. The second time, the garage replaced the gas cap. Then the check engine light turned on again the next day. So, the third time, the garage performed maintenance/repair on the vapor can purge solinoid and the EVAP canister purge solinoid. Of course, three days after driving my car, the check engine light turned back on. I’ve contacted the garage for the fourth time now. I explained that their diagnostics have obviously been exhausted, and they aren’t really sure what the problem is. I’m going back in a few days to speak to the lead mechanic hoping to be compensated for their guess-work or at the least to be given an honest “I don’t know” answer. Any suggestions?
"I’m hoping that someone can provide me with some insight into a check engine light issue."
You’ve Come To The Right Place . . . Maybe . . . Pull Up A Chair.
Let Me Ask A Question And I’ll Tell You A Little Story.
Question
Do you know if the same DTC (diagnostic trouble code) is turning on the light each time and would you know or can you find out if it’s PO440 ? That code would ordinarily lead one to believe that a problem exists in the purge solenoid, or that the canister is plugged, or a gas cap is installed wrong or is not working properly.
Little Story
However, when 2000, 2001, and 2002 Sunfires were built some of them had their EVAP solenoid wiring harness misrouted around the rear ABS (antilock brake) wiring harness. This mistake caused rubbing or chaffing damage to the EVAP vent solenoid harness and away we go - CHECK ENGINE light and code PO440.
So have the mechanic check at the right rearr corner of the fuel tank and see if there’s a problem like the one I’ve described. If so, have the harness replaced or repaired and rerouted so it doesn’t wrap under the ABS harness.
How’d I do ?
CSA
You did Good, as always but take into consideration,
The EVAP large leak test applies vacuum to the evaporative emission (EVAP) system and monitors vacuum decay. The powertrain control module (PCM) monitors the fuel tank pressure (FTP) sensor signal to determine the vacuum decay rate. At an appropriate time, the PCM turns the EVAP canister purge valve ON (open) and the EVAP vent valve ON (closed). This allows the engine to draw a vacuum on the EVAP system. At a calibrated time, or vacuum level, the PCM turns the purge valve OFF (closed), sealing the system, and monitors the FTP sensor input in order to determine EVAP system vacuum. If the system is unable to achieve the calibrated vacuum level, or the vacuum level decreases too rapidly, DTC P0440 will set.
The vacuum line failure or solenoid problem could also be an issue in addition to the possible wire damage.
Thanks for the story! I’ll definitely discuss this issue with the mechanic/technician when I go in next. Also, I know that the DTC was P0446 the first time I took the car in. Since they seemed to be focusing on the same issue, I assumed that the same DTC continued to appear. I’ll certainly ask.
Barkydog–I’m hoping that by the second maintenance of the EVAP system, they would have determined whether or not the system is functioning properly. However, I will take this info. with me when I speak with them next. Thanks!
Well, I took my car into a GM dealership, and they identified the DTC as P0446. They performed their diagnostics and told me that the canister purge solenoid wasn’t plugged in. They plugged in the component and again performed their diagnostics–then explained that they could identify no issues. So, previous to the GM dealership, I had been taking the car into a national chain mechanic. It’s possible that through all their diagnostics (and money I spent) that they simply didn’t plug the component in. Well, three days after picking the car up from the dealership, the check engine light is back on. I haven’t had the code read yet, and I’m crossing my fingers that there is at least a different problem. Now, I’m even more stumped.
“previous to the GM dealership, I had been taking the car into a national chain mechanic.”
The chance of finding a truly competent and honest mechanic at one of the national chains is tantamount to the chance of finding a virginal woman in a house of ill repute–i.e., technically possible but not very likely.
I strongly suggest that you ask friends, neighbors, relatives, and co-workers for recommendations on an independent mechanic in your area.
Just one more thing, make sure you are not overfilling the gas tank. You have to stop filling with the first click of the handle, don’t keep topping off. That causes the canister to saturate and can give you this code.
VDCdriver–I certainly found out the hard way that it’s important to avoid the national chains. However, I had more confidence taking the car to a GM dealership service center. At this point I’m assuming something more involved is wrong with the car. I’ve had the car examined at two different places, and the same issue is arising. Thanks.
Keith–Interestingly, at the times the check engine light returned, I was partially through or almost entirely through a full tank of gas. Thanks.