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Malfunction Indicator Lamp

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Silver bullit, Oct 18, 2015.

  1. Silver bullit

    Silver bullit Right Lane Cruiser

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    I was driving my 2009 Prius today when the malfunction indicator lamp came on. The gas gauge had just gone from 2 pips to one pip. The one pip was not blinking. No other lights came on and the car seemed to be driving normally. On the way home I filled up the gas tank. When I started the car after getting gas the malfunction indicator lamp had disappeared and the car drove normally. Any input from the Prius gurus? Thank you.
     
    #1 Silver bullit, Oct 18, 2015
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Do you mean the check engine light (amber icon in the shape of an engine) when you say "malfunction indicator lamp"?

    If yes, then perhaps the gas cap was loose (must tighten to at least one click), or maybe the engine was starting to receive an intermittent fuel flow due to the low level in the tank.
     
    #2 Patrick Wong, Oct 18, 2015
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  3. Silver bullit

    Silver bullit Right Lane Cruiser

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    That's the icon but the manual calls it the malfunction indicator lamp. So that's the check engine light?
     
    #3 Silver bullit, Oct 18, 2015
  4. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Yes.

    If that warning icon should reappear (and a low fuel level or loose gas cap is not the issue) then have the DTC retrieved. Maybe the engine has an intermittent misfire, as just one possibility. Or maybe the engine coolant valve is starting to act up.

    Also, check all engine compartment fluid levels: engine oil, engine coolant (at the radiator itself, not just at the overflow container) and inverter coolant. While you are at it, make sure the brake fluid and windshield washer fluid are at good levels.
     
    #4 Patrick Wong, Oct 18, 2015
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  5. Silver bullit

    Silver bullit Right Lane Cruiser

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    Thank s I will do that
     
    #5 Silver bullit, Oct 18, 2015
  6. bisco

    bisco cookie crumbler

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    how many miles on her?
     
    #6 bisco, Oct 18, 2015
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  7. Silver bullit

    Silver bullit Right Lane Cruiser

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    #7 Silver bullit, Oct 19, 2015
  8. Silver bullit

    Silver bullit Right Lane Cruiser

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    The DTC is P1121. I see this is the engine coolant valve. I guess I have to take it to a shop. Is it OK to drive it. Radiator coolant is up to the brim. I can read coolant temperature on my scanguage. Thank you I just copied this post from another thread so I will give it a shot

    "2005 Prius, 130K, Check Engine Light came on. Code: P1121 Problem: Coolant Control Valve may not be operating correctly.

    Per CA Emissions Warranty, repair was completed by dealership free of charge. I called Toyota directly at first, they said it was not covered by warranty. Then I checked with local dealer who ran the vin and said it was covered and fixed it that day. Stoked for great local dealership service."
    That would be nice as I see that this repair is several hundred dollars.
     
    #8 Silver bullit, Oct 19, 2015
    Last edited: Oct 19, 2015
  9. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Assuming that the radiator coolant level is full and you do not see an engine overheating warning, then you can drive the car indefinitely as-is. A stuck engine coolant valve can result in the cabin heater not working well and/or the engine emissions control at a cold start may be impaired.
     
    #9 Patrick Wong, Oct 19, 2015
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  10. Silver bullit

    Silver bullit Right Lane Cruiser

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    #10 Silver bullit, Oct 19, 2015
    Last edited: Oct 19, 2015
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