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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. Patrick Wong

    Patrick Wong DIY Enthusiast

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    1. Although the NA Prius coolant capacity is ~ 9 US quarts, when the coolant is drained the refill capacity is only 6.5 US quarts (because the cabin heater core and the coolant heat recovery system contains substantial coolant) so there was very little coolant actually circulating in the engine, given that you had to add 4 quarts.
    2. Therefore, I expect that either your engine cooling system has a very significant coolant leak and you need to figure out where that is - or the cylinder head gasket is leaking and the coolant is being burnt in the engine combustion chambers. What does the engine oil look like on the dipstick - any milkiness which would indicate coolant in the oil?
    2. I agree that the engine compression needs to be checked or a cylinder leak down test performed, to see if engine damage has in fact occurred due to overheating. That definitely could cause the cylinder #1 misfire and this should be done sooner vs. later.
     
  2. allen_gamble

    allen_gamble Junior Member

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    I have waiting to see if there is a consensus here before doing anything else. Today I just added some Gumout Fuel System Cleaner to the tank and took it out on the highway for the first time in a week. It only misfired if I drove very aggressively, but did not misfire if I accelerated slowly and smoothly, and I'm still seeing the same codes.

    Engine oil is clean, not milky, it's been less than 170 miles since my last oil change.

    Something I had not mentioned before which I've been told is probably crucial is that before my last oil change I added almost 2 quarts of oil instead of changing it when it was due for the previous oil change, the change oil light had flashed a few times but it was not overfilled.

    A cylinder leak down test looks like something I'm not capable of doing, and I would need to spend a little money for the gauges needed to check the compression but it looks like something I can do easily.

    Approximately how much would it cost for me to have a dealer flush the cooling system, and should that be my first step?
     
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    How many miles have you driven since refilling the radiator coolant last Tuesday? Have you checked the radiator fluid level since then?

    I would defer flushing the cooling system until you've figured out 1) why the engine is misfiring, and 2) where the engine coolant is going.

    Regarding the cylinder compression test, use Mini VCI to spin the engine at the proper speed, and buy a cylinder compression gauge with the appropriate fitting to screw into the spark plug holes.
     
  4. allen_gamble

    allen_gamble Junior Member

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    I estimate I've driven at the most 100-120 miles since Tuesday, including just less than 70 today. No change in radiator fluid. I've been using a Bluetooth plug/Android/the Torque app for my OBDII codes, Mini VCI won't work for me.
     
  5. bisco

    bisco cookie crumbler

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    you may need to find an old laptop to run the tech stream software.
     
  6. allen_gamble

    allen_gamble Junior Member

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    I drove approximately 150 miles today in an effort to circulate Gumout through my ignition system. I used back-roads to drive to and from a town about 35 miles away and then turned the car on and off before redriving to and from that town using the highway (going up to 70mph). I added gumout when I last filled up my gas tank and today I drove until I had used half a tank, then added more gumout and reset the OBDII codes. Now the cyclinder is no longer misfiring and I am left with codes P1116 and P1121.
     
  7. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I suggest you clear the DTC, and drive the car another 500 miles. If at the end of that time the only DTC are P1116 and P1121 and the radiator coolant remains full (as viewed by removing the radiator cap), then it will be time to replace the engine coolant valve.
     
    allen_gamble and valde3 like this.
  8. allen_gamble

    allen_gamble Junior Member

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    Is your 500 mile number precise? My plan is to add more Fuel Injector cleaner when I'm closer to empty, drive it for a week, and then probably replace the valve. I anticipate driving about 320 miles this week and would have to go out of my way tomorrow to drive the extra 180 miles. I will be using the Chevron fuel injector cleaner, not Gumout. Gumout was on clearance, I just happened to get 2 bottles of Gumout Fuel Injector Cleaner for about the same price as the Chevron. I read another thread praising the Chevron product so I bought it today.
     
  9. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I suggest you log enough time to make sure the engine misfire problem has gone away. Its up to you, regarding how long you wait before replacing the valve.
     
    allen_gamble likes this.