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Check Engine Light

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by EH2016, Aug 9, 2016.

  1. EH2016

    EH2016 Junior Member

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    Hey! Our 2008 Prius has about 111,000 miles on it and the check engine light has been coming on and off for a day or two at a time in the past few weeks. I've seen some things online about this possibly being (1) an electrical connection issue or (2) a inverter coolant pump issue. I've been thinking about taking the car in to a local Toyota specialist to check things out, but I thought I'd check with y'all first. Can anyone help me with this?
     
  2. andrewclaus

    andrewclaus Active Member

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    Without diagnostic test codes (DTCs), we're simply guessing. A zero-cost option is to try getting a free scanner read at your local auto parts store--some will do that, call around. But those scanners do not read all Prius-specific codes--you get what you pay for. The dealer will charge about $100. Most DIYers here buy a MiniVCI for about $25 and use an old Win7 laptop for full capability.

    Report back when you get something.

    When this symptom showed up on my Prius, it was the three way coolant valve, a mostly non-essential item. If it were the inverter pump, you'd probably have noticed a harder failure by now. Many minor intermittent issues will reset themselves, but should not be ignored. A two- or three-digit cost will quickly become a four-digit cost.
     
  3. edthefox5

    edthefox5 Senior Member

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    Most posts we see here concerning an intermittent cel is because the engine has no oil in it. Its extremely low so when you go around a corner the tiny amount that it does have sloshes around and the oil pickup runs dry and the oil pressure which is already very low then goes to zero. It will then throw the check engine light. Usually resulting in permanent engine damage.
     
  4. JC91006

    JC91006 Senior Member

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    If I was guessing, I'd say bad catalytic converter
     
  5. EH2016

    EH2016 Junior Member

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    Okay. I'll try to get a free local scan and then report back. Thanks!
     
  6. EH2016

    EH2016 Junior Member

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    Interesting. I get my oil changed religiously—never going over the recommended mileage between changes. Could this still be an issue?
     
  7. EH2016

    EH2016 Junior Member

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    Yikes. I'll start with a free scan of the codes and then take it in to a shop, if necessary. Will report back on what I find out!
     
  8. andrewclaus

    andrewclaus Active Member

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    Yes, it certainly could be an issue. If you're not in the habit of checking the dipstick every couple of fill-ups, now's the time to start. It's not unusual for an aging Prius to begin consuming oil with no other symptoms, no other problems, and continue to work fine for years. Check that dipstick! Keep an eye on the coolant reservoirs, too.
     
  9. EH2016

    EH2016 Junior Member

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    Good idea. I honestly haven't been, but just did and the oil level is perfect, as are the other coolant reservoirs.
     
  10. andrewclaus

    andrewclaus Active Member

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    And keep in mind many oil change places routinely over-fill the Prius. If you put in the rated capacity, the level is slightly high on the dipstick. So what's perfect now may mean you've already consumed several ounces. Again, keep an eye on it and make a habit of it. 5000 miles is a long way to go without checking the oil at this point in the car's life.
     
    junoon likes this.
  11. EH2016

    EH2016 Junior Member

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    Okay, folks. I've done three things since my first post: (1) cleaned out and reconnected the gas cap, (2) got the oil changed and added a touch more coolant, and (3) got a free scan of the codes, which produced "P1121: Manufacturer Control Fuel Air Metering." After all of that, the check engine light is off. Who can tell me what's going on?
     
  12. EH2016

    EH2016 Junior Member

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    ---

    I've done three things since my first post: (1) cleaned out and reconnected the gas cap, (2) got the oil changed and added a touch more coolant, and (3) got a free scan of the codes, which produced "P1121: Manufacturer Control Fuel Air Metering." After all of that, the check engine light is off. Thoughts on all of this?
     
  13. EH2016

    EH2016 Junior Member

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    Location:
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    Two
    ---

    I've done three things since my first post: (1) cleaned out and reconnected the gas cap, (2) got the oil changed and added a touch more coolant, and (3) got a free scan of the codes, which produced "P1121: Manufacturer Control Fuel Air Metering." After all of that, the check engine light is off. Thoughts on all of this?
     
  14. andrewclaus

    andrewclaus Active Member

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    P1121 is the coolant control valve, not fuel air metering, and is a fairly common code, especially when coupled with low coolant. But I'm concerned about the confusion--something's wrong. Maybe the scanner or operator read it wrong. P1121 the code I referred to in post #2. You can live with this one, and the worst case is it'll affect cabin heat come winter. But the check engine light will probably come back soon, annoy you, and may mask another problem.

    Keep a very close eye on coolant level. Check in the COLD radiator, not the reservoir, by removing the upper splash shield (six annoying plastic fasteners). If you can't see coolant in the radiator neck, you need to find the leak.