EVAP system / AC problems :(

Discussion in 'SN95 V6 Mustang Tech' started by JimWall, Apr 14, 2010.


  1. JimWall

    JimWall New Member

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    Hello everyone,

    I have a 2000 V6 convertible mustang. I love my car. It's got 134,000 miles on it. Never had a real bad problem before...but in the last few days the "Service Engine Soon" light came on, AND the AC doesn't seem to be working any more.

    From what I've looked at online, they aren't related.

    I went to Autozone, and the code was P0445, which is an EVAP system leak/error. From what I've read online, it could be:

    1)Rear O2 sensor is stuck open,
    2) O2 sensor wires are damaged.
    3)Purge Control wires are damaged,
    4) Purge control valve needs to be replaced
    5) could be a leak in the fuel neck filler.

    I don't know what any of these things are, or where they are located. How would you suggest I go about having these things checked? Could anyone recommend a good source to find pictures of what I am looking for? Where to locate parts if i need them? Or should I just take it into a shop?

    The second issue is my AC went out. I can still hear the fan running, and it seems like the air is still cool, BUT it isn't blowing out of the vents. I don't know what would cause this. Like I said, when i turn it on, I can hear a fan turn on, but no air blows out. Any ideas?

    -Jim
  2. Aeroman

    Aeroman New Member

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    P0445= Purge control valve short circuit.
    Check the purge control valve, which is located near the firewall, on the air intake side of the engine below the shock absorber upper mounting plate. The purge valve is a small cylindrical shaped device connected with two vacuum pipes in a tee configuration. It also has an electrical plug which is the control from the PCM. Basically you need to check for signal voltage at the plug while the engine is warm & RPMs are at about 1500. The purge valve should cycle on & off at intervals. If not then look for damaged wiring or broken insulation, which could be shorting to ground or possibly corrosion in the plug/ wiring. The purge valve could also be faulty, causing the short circuit condition. This you can check with a multimeter (set on Ohms).

    The AC problem is not connected to the evap circuit.

    A purge valve should not cost too much & you can test the old one (after removal) by connecting up 12v & listening to the solenoid "thump" which should open up the air flow through the valve. If not ...replace the purge valve.

    HTH Aeroman.
  3. JimWall

    JimWall New Member

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    Correction: P0455 NOT P0445

    I just realized that the error code was P0455 not P0445 which is a large evap leak. I am thinking I will have to bring it to a garage. Anyone know how much it might cost to have this looked at and repaired? estimates?

    What about the AC? Any ideas about that?

    I've been saving up to buy a new Mustang...but I'd like to wait as long as I can, and keep the 2000 running... (the convertable top also leaks in heavy rain)

    do you think it's time to just let it go?
  4. Aeroman

    Aeroman New Member

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    Check for split or disconnected evap lines. That Purge flow valve could be stuck open. Check your filler cap gasket. Check your Tank filler tube rubber at the point of entry in the fuel tank.
    AC I have no idea, may be a simple re-charge of refrigerant.
  5. wmburns

    wmburns SN Certified Technician

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    P0455 - EVAP Control System Leak Detected

    For the AC problem, first inspect the small vacuum line from the engine compartment into the passenger compartment. I suspect it is damaged which is preventing the vacuum operated vacuum damper motors from adjusting the dampers. A double check is if the air is coming out of the defrost vents.

    For the EVAP problem, inspect all of the vapor lines. I suspect the problem is between the VMV located inside the right hand fender well and the left rear charcoal canister. Start 1st at the canister.

    Remember that the gas vapors cause the lines to rot from the inside out.

    >>from Ford service CD
    P0455 - EVAP Control System Leak Detected (No Purge Flow or Large Leak)

    The PCM monitors the complete EVAP control system for no purge flow, the presence of a large fuel vapor leak or multiple small fuel vapor leaks. The system failure occurs when no purge flow (attributed to fuel vapor blockages or restrictions), a large fuel vapor leak or multiple fuel vapor leaks are detected by the EVAP running loss monitor test with the engine running (but not at idle).

    • After-market EVAP hardware (such as fuel filler cap) non-conforming to required specifications
    • Disconnected or cracked fuel EVAP canister tube, EVAP canister purge outlet tube or EVAP return tube
    • EVAP canister purge valve stuck closed
    • Damaged EVAP canister
    • Damaged or missing fuel filler cap
    • Insufficient fuel filler cap installation
    • Loose fuel vapor hose/tube connections to EVAP system components
    • Blockages or restrictions in fuel vapor hoses/tubes (items also listed under disconnections or cracks)
    • Fuel vapor control valve tube assembly or fuel vapor vent valve assembly blocked
    • Canister vent (CV) solenoid stuck open
    • Mechanically inoperative fuel tank pressure (FTP) sensor
    Check for audible vacuum noise or significant fuel odor in the engine compartment or near the EVAP canister and fuel tank.

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