Edmunds Answers



  • karjunkie 03/15/09 4:41 pm PST

    Evaporative Emission Control System Pressure Sensor Low Input indicates a low voltage problem in the Fuel Tank Pressure Sensor (FTPS). What the fuel FTP sensor does is convert fuel tank absolute pressure into electrical signals and inputs the signal to the ECM/PCM, (Computer). First thing to do is make sure the gas cap is good and tightened properly. Given the gas cap's age, you may just want to replace it as the seal may be dry and leaking which would give you a low pressure signal. Then check the vacuum lines and wiring at the FTPS (Location-Fuel Tank) to be sure they are good, clean and tight. Barring a wiring problem it can be a bad FTPS. I do not think you need a new charcoal canister in any event. Good luck and let me know how it goes!

  • rodeoshooter 03/15/09 8:07 pm PST


    Thanks for the tip. We checked the gas cap and I did replace the canister and the solenoid on the recommendation of my mechanic. Friday he was talking about a lack of pressure due to a leak in the line from the canister. Previously he had talked about a service bulletin which was supposed to talk about a bad electrical connection located by the fuel tank. But then on Friday he was talking about sending me to a dealer to check for the leak. He has ordered a gauge to check the pressure in the lines running from the canister. Does that sound right?



  • karjunkie 03/16/09 8:08 am PST

    Al, yes it does sound right. As I noted before, it could be a wiring problem sending the wrong signal. Also it could just be a leaking or loose hose in the EVAP system that is resulting in a low pressure condition.

  • dave8697 03/17/09 10:13 pm PST

    My '96 Riv set that code 3 years ago. I changed gas caps and nothing changed. The charcoal canister is in rear axle area with long vacuum lines back to engine. The computer runs a check at every startup to check vac lines for a leak. There is over 25 feet of hose that could have a pinhole. I decided to put a sticker over the orange warning light and allow a tiny amount of gas vapors to leak into the atmosphere. Ignoring it has never caused issues. My sticker fell off recently, though. I have to replace it. I was able to detect a mass air flow sensor failure due to engine stumble and had codes read. A new one showed up. MAF had to be replaced. Not one I could ignore.

  • rodeoshooter 04/27/09 10:29 pm PST


    Thanks for the response. I replaced the Filter Canister and just replaced the fuel tank cap. Still happening. Went out of town this weekend and I am still just getting 13 MPG on the highway with the engine that was replaced in June of 2007. Can't figure out what is going on and the codes are pissing me off.


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