2005 Prius - Error codes P0301, P0138, P1116, P1121

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by allen_gamble, Jul 6, 2015.

  1. allen_gamble

    allen_gamble Junior Member

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    My Prius began running rough a few days ago and an ODB code told me the problem was with an ignition coil, so I replaced Ignition Coil #1 (on the left) and it ran well for a few days but I didn't drive it much. Today I left to pick up my daughter for vacation and it began to run (shake) even harder, sporadically. Now I'm worried I will have to pay for extensive repairs because of these codes: P0301, P0138, P116, P1121. How much of this can I repair myself if I only have ordinary hand tools, not power tools?
     
  2. allen_gamble

    allen_gamble Junior Member

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    I couldn't post links until now...

    As for code P0301, I've read this thread: 2005 Prius P0301 misfire | PriusChat where there are instructions for replacing the injector, which looks like something I can do.

    P0138 seems to be fixable via an oxygen sensor replacement according to: P0138 Toyota Oxygen Sensor Circuit High Voltage Bank 1 Sensor 2 OBDII Engine Light Trouble Code | Engine-Codes.com

    P1116 concerns engine coolant and seems more troublesome according to P1116 Toyota Coolant Temperature Sensor Circuit Stack for Coolant Heat Storage System OBDII Engine Light Trouble Code | Engine-Codes.com - I have no idea what to do.

    This thread also mentions that P1121 means the Coolant Flow Control Valve Position Sensor Circuit (is) Stuck 2007 Prius P1116 code and coolant control valve issues | PriusChat

    So it looks like I need to replace the injector, an oxygen sensor, and a coolant control valve. I haven't replaced the spark plugs in 100,000 miles (Replaced them at 65k, it's at 165k now (!) Am I missing anything?
     
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  3. bisco

    bisco cookie crumbler

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    i think spark plugs are every 120k. and the belt is in there somewhere. other than that, it's all fluids.
     
  4. Patrick Wong

    Patrick Wong DIY Enthusiast

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    1. Remove the spark plugs and inspect them, especially the plug for cylinder 1. If there is any doubt about their condition, replace them now.
    2. Check the radiator coolant level (in the radiator itself, not just the overflow reservoir) because a low level can cause the last two DTC you listed.
    3. If the spark plugs are good then you may need to replace the cylinder 1 fuel injector, but make sure you do not damage the O-rings when reinstalling the fuel rail on the injectors and inserting the injectors into the intake manifold.
    4. Regarding the oxygen sensor fault code, I would wait until the misfire has been corrected before worrying about that. After the misfiire is gone, clear the DTC and see if the oxygen sensor DTC returns.
     
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  5. allen_gamble

    allen_gamble Junior Member

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    I bought a spark plug (and the tools needed to replace it) so I'm going to replace it, but is the following quote correct? "You should see coolant within one inch of the opening" I ask because my overflow reservoir is full but I don't see coolant when I look down into the opening of the actual radiator.
     
  6. bisco

    bisco cookie crumbler

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    yes, you need to see coolant. get a gallon from a toyota dealer and top up.
     
  7. allen_gamble

    allen_gamble Junior Member

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    Coolant is filled, sparkplug replaced, but the area where the spark plug connects is contaminated somehow.
    If I temporarily mount a clean spark plug in it , screw it in and then pull it out, it comes out with a white powder on the end.
    I replaced the spark plug but could not remove the MFA to clean it as I had planned, because I can't remove the screws. I felt as if I were stripping them instead of unscrewing them.

    After a few test drives it began shaking again and these are my current codes:
    P0301 Misifre Detected
    P1121 - according to the following video the part (a valve) costs about $60 and taking it to the dealer costs about $500. Are these two codes - P0301 and P1121 - somehow connected?
     
    #7 allen_gamble, Jul 7, 2015
    Last edited: Jul 7, 2015
  8. Patrick Wong

    Patrick Wong DIY Enthusiast

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    The radiator coolant level should be at the very top of the neck when you remove the cap. How much coolant did you have to add to bring the level up to full?

    I do not understand this. Are you talking about the threaded hole in the cylinder head that the spark plug screws into; or are you talking about the spark igniter which provides high voltage to the spark plug?

    What is an MFA (besides Master of Fine Arts)?

    No. Depending upon how much coolant you had to add, you may have trapped air in the system. How well does the cabin heater work and do you hear air bubbling in the cabin heater core? If the heater does not produce lots of heat or if you hear air bubbles then you need to work on getting the air out before you worry about changing the valve.
     
  9. valde3

    valde3 Senior Member

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    How much coolant did you need to add? Are you sure you did get all the air out? This is related to P1121.

    But I think you should focus on P0301. If end of the igniter is corroded you probably just need new one. But it’s easy to test. Just switch cylinder 1 and 2 igniters around. If you then get misfire in cylinder 2 you know it’s faulty igniter.

    If you mean MAF and you can’t get it off you can still clean it either by just leaving it in its place or removing it with the bottom of air cleaner box.
     
  10. allen_gamble

    allen_gamble Junior Member

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    I added one bottle of coolant, followed the instructions for bleeding out air precisely, heat works fine.
    I meant MAF, not MFA.
     
  11. allen_gamble

    allen_gamble Junior Member

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    When you say "igniter" are you talking about something other than the "ignition coil"? So far I have I installed an ignition coil and a new spark plug. The corrosion/powder/gunk that I discovered is down inside of the well where I installed the spark plug which is the same well/cavity where I insert the ignition coil. I can't see down inside of there.

    Also, and this may be a stupid question, but I think a fuse is missing from the relay box (photo attached). I had my oil changed a few weeks ago and it was mentioned that I may have had mice in my engine compartment at some point since the air filter looked chewed up - are any of these things relevant?
     

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    #11 allen_gamble, Jul 8, 2015
    Last edited: Jul 8, 2015
  12. bisco

    bisco cookie crumbler

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    could the head gasket be allowing coolant into the cylinder?
     
  13. valde3

    valde3 Senior Member

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    Check the wiring going into cylinder one ignition coil and fuel injector.

    This seems pretty weird. You had corrosion in spark plug tube one which means you had water in there. Water in there will cause misfires and can break ignition coil (igniter) but you replaced that and it’s still not working. There wasn’t any water there? Is there corrosion in other spark plug tubes? Maybe still try to switch the ignition coils around?
     
  14. allen_gamble

    allen_gamble Junior Member

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    Thunderstorms were forecasted for today and tomorrow so I have not done any work on the car or driven it. I can't see down into the "spark plug tube" so I can't tell if there is water in there but it looks like it is a safe assumption. Can I do anything to drain the water or dry it out? What is the next step?
     
  15. allen_gamble

    allen_gamble Junior Member

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    Someone more knowledgeable than I would have to answer this question.
     
  16. allen_gamble

    allen_gamble Junior Member

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    The wiring seemed dry and intact but I will try to switch the ignition coils around with the new one just to see if the error codes change, and visually check the other ignition coils to see if the corrosion is consistent across all four. If it is, then I know that's not the problem. The #1 Ignition coil / Sparkplug is the easiest one to access and work on so up until now I was thankful that I didn't have to touch the others.
     
  17. valde3

    valde3 Senior Member

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    Water in spark plug tube will cause misfires and can damage ignition coil and spark plug. So you need to get rid of the water and stop it from entering. Probably you just need new cowl (area under windshield wiper mechanism) seals.

    How did you clean the water out when changing the spark plug? Compressed air is probably the easiest way.
     
    #17 valde3, Jul 9, 2015
    Last edited: Jul 9, 2015
  18. Patrick Wong

    Patrick Wong DIY Enthusiast

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    The box in your photo is only for relays, there are no fuses. The box lid contains a map that shows what each relay does. See what the missing position is for.

    Regarding mice chewing up the engine air filter, put 1/4" wire mesh screening across the intake which is near the windshield washer container. You can buy this at places like Lowe's or Home Depot as well as your neighborhood hardware store.

    The spark igniter is aka ignition coil.

    What does "one bottle of coolant mean"? Toyota Super Long Life Coolant is sold in one US gallon containers. Did you actually have to add one gallon of coolant? If so your engine has a big problem with a coolant leak somewhere and the most likely place is at the engine coolant pump bearing. Look at the pump pulley for a pinkish residue inside. Also look at the air conditioner compressor housing for residue deposited on the top.

    When you removed the spark plug, any liquid in the well would have dripped into the cylinder. If there was just a tiny amount, then no problem. If a substantial amount entered, that might cause a hydro lock problem which would result in engine damage.

    If there is a powdery residue in the one spark plug well which is not present in the others, then liquid has been entering. Something needs to be done about it.

    See whether use of a mirror allows you to view the spark plug well. An alternative is to remove the sheet metal tray (which houses the windshield wiper motor) so you can easily look down into the cylinder head area.

    Regarding the possibility of water dripping onto the engine head, the solution would be to apply a bead of black sealant on the seam between the two plastic cowl pieces.

    bisco mentioned the possibility that engine coolant ls leaking into the spark plug well due to a failed cylinder head gasket. That can be determined by inspecting the spark plug well as mentioned above.
     
    #18 Patrick Wong, Jul 9, 2015
    Last edited: Jul 9, 2015
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  19. allen_gamble

    allen_gamble Junior Member

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    I added one bottle/one gallon of Toyota Super Long Life Coolant. I see no pinkish residue anywhere. I was able to use a mirror to look into the well and saw nothing obvious - no liquid, though the ignition coil did have some white residue on it when I pulled it out. I used an air compressor to spray out the well and when I drove away from the gas station every light in my dashboard was lit up. After resetting the only codes left are P0301 and P1121, and (only) the check engine light stays on.
     
  20. valde3

    valde3 Senior Member

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    If you had to add that much coolant you need to bleed the cooling system. Bleeding North American Gen2 Prius isn’t easy. But you will find lots of information online. Bleeding may fix your P1121 since air in cooling system can cause that. But you should also figure out why there was so little coolant in the system.

    Clean the water out of spark plug tube, switch coils around and clean codes to make sure that fault stays with cylinder one. If it does check the wiring carefully and (maybe) do compression test (and check the spark plug). If you still found no problem switch injectors around (you may need new injector seals) clean codes and see if it’s still cylinder one that misfires.
     
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