Exhaust fumes/malfunction light issue

Discussion in 'Gen 2 Prius Main Forum' started by kayak99, Dec 31, 2009.

  1. kayak99

    kayak99 Junior Member

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    Now that the holiday has arrived and dealers are closed I have an issue I'd like to get an opinion on from forum members.

    This afternoon my wife came home from work in her 2009 Prius (< 20,000 miles on it) and told me her malfunction light is on. I looked, found no obvious problem so we drove it out to dinner.

    We immediately smelled fumes. I had just put my snowblower away so I thought the fumes I smelled had been those but no, it's definitely the Prius. The fumes lessen when I pick up speed as well as when I turn off the fan blower but that's difficult to do in the dead of winter.

    I plan on contacting the dealer if he's open Saturday but has anyone experienced this? It does not appear to be the muffler.

    Thoughts?
     
  2. Bobsprius

    Bobsprius BobPrius

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    I don't have an answer but since your in PA, could there be something whereby when driving and since we have snow and ice here in Buffalo, maybe somehow someone drove over a larger ice chunk in the road and dislodged something from the exhaust or catalytic converter????

    That would be my thought based on what you stated with the fumes.

    I noticed today coming to work the truck ahead of me dropped a "large" snow/ice boulder from his undercarriage and I dodged it last minute...it would have certainly hit the exhaust and undercarriage had I not...

    Just my thought....
     
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  3. kayak99

    kayak99 Junior Member

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    I might try to run the car onto some ramps tomorrow (New Years Day) & take a close look. Thanks. Surprising amount of fumes coming in when the heater fans are on though.
     
  4. Bobsprius

    Bobsprius BobPrius

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    I would definitely take a look underneath to see if something came apart, dislodged etc.

    It not something that should really happen, but that's about all I can think of with the situation you described and with the malfunction light, it could be related to the exhaust system.....

    Be curious to what you find....I can't believe your Catalytic Converter would have gone bad at that mileage....
     
  5. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I suggest that you look at the fuel line and fuel rail that connects to the four injectors. My guess is that you have a fuel leak.

    If you have a leak, it is a fire hazard to drive the car since the fuel line is pressurized to at least 43 psi. Suggest you park the car outside, away from any buildings or anything else that you don't want to catch on fire... :eek:
     
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  6. Bobsprius

    Bobsprius BobPrius

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    Pat,

    That's a scary thought with so little miles...Have you heard of this happening in the past???:confused:
     
  7. kayak99

    kayak99 Junior Member

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    It's definitely engine exhaust fumes we smell, not gas fumes.
     
  8. Patrick Wong

    Patrick Wong DIY Enthusiast

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    No.

    How do you tell the difference between unburned HC coming out of the exhaust, vs. gasoline fumes?

    In either case, the car is unsafe to drive. If exhaust fumes, there must be a leak in the exhaust system near the engine.
     
  9. kayak99

    kayak99 Junior Member

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    Seriously, you can't tell the difference between exhaust fumes and raw gasoline fumes? They are quite different. Next time you fill up, compare the gas going into your tank and the smell coming out your tailpipe. The smell coming out of our vents is the same as would come from your tailpipe.

    Yes, I am very aware it is unsafe. My question was whether anyone else had experienced this and, if so, what was their cause. In my life time I have had vehicles with exhaust problems, including one where a friends catalytic converter was yanked from under his and never did fumes come through the vents.

    This could be a gasket issue but I'll look closer in the morning. Also, don't forget, the "malfunction" light is lit. I doubt a gas leak would produce that alert. More likely an exhaust issue would.

    Thanks
     
  10. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Given that you have a warning light on (I assume you mean the amber check engine light?) and are sure that the smell is exhaust gas, maybe an air/fuel ratio sensor or oxygen sensor was physically impacted by road debris, causing the exhaust gas leak and the CEL to come on.
     
  11. kayak99

    kayak99 Junior Member

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    That's possible. I put the car on front ramps and the exhaust system appears intact. I'm not certain where that sensor is located but I see no visible signs of debris impact.

    The light on is the one titled "malfunction indicator lamp" and it does say "check". As you probably know, according to the manual there is a malfunction in the electronic hybrid system control, throttle control or transmission control systems.
     
  12. Patrick Wong

    Patrick Wong DIY Enthusiast

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    If you can get under the engine, then you might be able to look at the exhaust manifold which is on the side of the engine facing the firewall. The air/fuel ratio sensor is mounted on the driver's side of the exhaust manifold. The oxygen sensor is mounted on the exhaust pipe, passenger side, downstream from the catalytic converter.

    The oxygen sensor is a more likely candidate for road debris damage, since it is lower to the ground.

    If you put the car into inspection mode so the engine will run continuously while the car is on ramps (firmly setting the parking brake and using blocks on the rear wheels) then you might be able to see (or hear) where the exhaust gas leak is coming from. Of course, do this only in a well-ventilated area and try not to breathe too much of the exhaust gases...
     
  13. kayak99

    kayak99 Junior Member

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    I jacked the car up and, without getting too far under it, I could see the exhaust manifold from the passenger side and all looked & sounded well. I had to do this on a flat albeit icy/snowy driveway so I didn't get far enough under it from the drivers side and couldn't see the sensor. With any luck the dealer will be open Saturday so I'll call.

    Curious though, if the sensor is out of wack, how would fumes get into the ventilation system? I was almost expecting something loose/cracked/broken at the exhaust manifold which could have explained it but the entire exhaust system (from what I could see and hear) appeared almost like new. Thanks
     
  14. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Suppose the oxygen sensor snapped off at the exhaust pipe. That would create a hole in the exhaust system which would allow exhaust gases to escape, rise up, and get sucked into the cabin ventilation intake.

    That would also cause a DTC and check engine light to appear as the sensor voltage would not fluctuate based upon varying oxygen levels in the exhaust gases, so the engine ECU would log the trouble code.

    Another possibility is that the gasket between the exhaust manifold and the exhaust pipe is loose, allowing exhaust gases to escape. The air/fuel ratio sensor would not produce the voltage swing expected by the engine ECU, resulting in DTC and check engine light to appear.

    If you have an exhaust system leak you should be able to hear a pfft-pfft-pfft sound as the engine is running and exhaust gases are escaping through the hole.

    A third possibility if the exhaust system is found to be intact: is the engine oil filler cap missing? If yes, then crankcase combustion gases can escape through the hole and then enter the cabin ventilation intake.

    The air leak via the oil filler hole allows unmetered air to enter the crankcase and then into the intake manifold via the PCV valve and hose. This makes the air/fuel mixture lean, causing a DTC and check engine light.
     
  15. EW3

    EW3 New Member

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    Wondering if you figured out what was causing this? I have a similar problem with my 2010 Prius.
     
  16. underdog

    underdog Junior Member

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    Was this exhaust in the cabin ever diagnosed? I have a similar issue with a 2007
     
  17. cthindi

    cthindi Member

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    Do you have a check engine light as well?

    If there is no check engine light, other possibility is leak at exhaust manifold. The manifold gasket may have to be replaced.
     
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