hiljak Posted November 29, 2006 Report Share Posted November 29, 2006 Hello all, I haven't been around in while (that's a good thing right?). Anyway, I have a problem with my STS... it's throwing a P0440 code (EVAP) and also a check gas cap message. I changed the cap with a new one from Caddy, same problem is still there. I can clear the code and the messge and engine light will be off for a day, then their back. Here's another wierd thing, once that code has been set (and is currently showing the light), I can't get gas with the engine running. It will take some gas into the tank, then spit it back out. Yes, you read that right, it spits the darn gas right back out! I think it may be pressurising the fuel system while that code is set. How does one go about troubleshooting this?? Thanks guys. James 1999 STS 65k 1995 STS 127k Link to comment Share on other sites More sharing options...
JimD Posted November 29, 2006 Report Share Posted November 29, 2006 Is P0440 the only code or are there other P codes (like 0442, 0452, 0453)? They could show as history codes but they are still important. Basically, your evap. system is not able to develop vacuum. Another code would narrow down the potential problem pieces. Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
BodybyFisher Posted November 29, 2006 Report Share Posted November 29, 2006 Hello all, I haven't been around in while (that's a good thing right?). Anyway, I have a problem with my STS... it's throwing a P0440 code (EVAP) and also a check gas cap message. I changed the cap with a new one from Caddy, same problem is still there. I can clear the code and the messge and engine light will be off for a day, then their back. Here's another wierd thing, once that code has been set (and is currently showing the light), I can't get gas with the engine running. It will take some gas into the tank, then spit it back out. Yes, you read that right, it spits the darn gas right back out! I think it may be pressurising the fuel system while that code is set. How does one go about troubleshooting this?? Thanks guys. Look in the top of the wheel well and see if the pipe that runs from the gas filler to the tank is corroded, your car is fairly new, it's just a thought, Mike We have seen these pipes rust Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
hiljak Posted November 30, 2006 Author Report Share Posted November 30, 2006 Hi guys, thanks for the replies. The other two P codes listed I didn't think were related. One is P1189 which is a bad oil pressure sensor which I haven't had a chance to change and the other is P1617 (history) glow plug short to ground (not sure about that one). I will check the pipe you mentioned and report back. Are there sensors which could be bad? Checked the pipe, it looks great. It seems to be coated in an "under coating" type of stuff. No visible rust or corrosion. Any other suggestions? James 1999 STS 65k 1995 STS 127k Link to comment Share on other sites More sharing options...
Cadillac Jim Posted November 30, 2006 Report Share Posted November 30, 2006 P0440 - Evaporative Emission (EVAP) System P1189 - Engine Oil Pressure (EOP) Switch Circuit P1617 - Engine Oil Level Switch Circuit If you mean by "It will take some gas into the tank, then spit it back out"that gas runs on to the ground from under the car, then BodybyFisher is probably right, there is a break in the filler tube. There is a connector from the fillter tube to the gas tank; you might look at that too. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
CadiKing Posted November 30, 2006 Report Share Posted November 30, 2006 ... Here's another wierd thing, once that code has been set (and is currently showing the light), I can't get gas with the engine running. It will take some gas into the tank, then spit it back out. Yes, you read that right, it spits the darn gas right back out! I think it may be pressurising the fuel system while that code is set. How does one go about troubleshooting this?? Thanks guys. hiljak, My understanding is not to add gas when the car is running, period... I don't remember why, but I got the information here... good luck.. my .02 Link to comment Share on other sites More sharing options...
Ranger Posted November 30, 2006 Report Share Posted November 30, 2006 I always fuel with the engine running. It never regergitates. Link to comment Share on other sites More sharing options...
JimD Posted November 30, 2006 Report Share Posted November 30, 2006 .... Here's another wierd thing, once that code has been set (and is currently showing the light), I can't get gas with the engine running. It will take some gas into the tank, then spit it back out. Yes, you read that right, it spits the darn gas right back out! I think it may be pressurising the fuel system while that code is set. How does one go about troubleshooting this?? Thanks guys. On your vehicle, there is a check valve (part of the on board refueling vapor recovery) at the base of the filler tube. Sounds like that check valve is stuck closed or being held closed somehow and that is preventing the fuel from flowing to the tank. Unless you are willing to do some hit or miss tearing things apart, I would run all the symptoms past your local friendly Cadillac dealer service manager. Go right to the top of the food chain. Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
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