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P1122, P0446,P0606,P0172

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Paul Schenck, Nov 30, 2018.

  1. Paul Schenck

    Paul Schenck Active Member

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    P1122 =Coolant Control Valve Position Sensor
    P0446= Evaporative Emission System Vent Control Circuit
    P0606 Engine Control Module / Power Train Control Module Processor
    P0172 = Bank 1 System too rich

    Electra, now with over 500,000 miles has a few issues.
    Last repair was a California Catalytic Converter, before that a Bank 2 O2 sensor.

    The P1122 I thought was taken care of when I replaced the coolant control valve though I noticed when I had done it that the plug connector was showing some oxidation on one of the pins. Now I’m wondering how to test the valve to determine if the connector is the problem.
    The P0446 has shown up a few times now and I’m going to locate it and swap it with the spare. Any idea where it’s located?
    Anyone know what the P0606 is all about?
    Or this P0172?


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  2. 05PreeUs

    05PreeUs Senior Member

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    Normally "too rich" is due to leaking injectors or a failed front "wide band" or "AFR" O2 sensor. Can also be low compression, bad plug or coil > weak or no spark, but you would expect a misfire DTC, which you do not have.

    BTW, there is no "bank 2", only Bank 1, front and rear O2s (front controls AFR, rear confirms that the cat is there and working).

    The CCV takes some power to operate, so corrosion can cause that code.
     
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  3. Paul Schenck

    Paul Schenck Active Member

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    Thanks, I can eliminate a few possibilities cat, front and rear O2 sensors good and reading well in their ranges (live-data from scan tool confirms) haven’t noticed misfire though it may be time to look at the plugs and coils though yes I would have expected a code were that happening.
    I’ve cleared all the codes and the only one remaining is P1122 Coolant control Valve position sensor. The P0446 , 0606, 0172 take a few trips to show up.


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  4. Patrick Wong

    Patrick Wong DIY Enthusiast

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    DTC P0606 means that the engine ECU has a CPU malfunction. The other DTC logged by that ECU are suspect until you have resolved that first issue. Resolution requires replacement of the engine ECU.
     
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  5. Paul Schenck

    Paul Schenck Active Member

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    Thanks Patrick, that a great explanation. I’ll dive into the my spare parts 2006 and locate the replacement


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  6. Paul Schenck

    Paul Schenck Active Member

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    IMG_7119.jpg
    Hey Patrick what do you know about these five wires leading to the connector for the coolant control valve. The harness in Electra was damaged by an old coolant leak, I replaced the pump but the code returned. Thought it must be the connection



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  7. 05PreeUs

    05PreeUs Senior Member

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    I do not see any corrosion or damaged pins in those at all.
     
  8. Paul Schenck

    Paul Schenck Active Member

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    Yes this is the replacement connector taken from my 2006 donor Pri


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  9. Paul Schenck

    Paul Schenck Active Member

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    This is the one that is suspect IMG_6925.jpg IMG_6924.jpg


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  10. 05PreeUs

    05PreeUs Senior Member

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    Oh, WAY worse than "suspect", more like JUNK.
     
  11. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Regarding P1122, you can measure resistance across the various pins of the wiring harness connector for the valve. Pins 1 and 2 should be around 40 ohms. Those pins are for the motor within that valve. Then the resistance across pins 5 and 6 should be 5,700 ohms which is both sides of the variable resistor which shows valve position. Pin 4 is attached to the arm of the resistor so the resistance to pins 5 and 6 will vary depending upon the valve position.
     
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  12. Paul Schenck

    Paul Schenck Active Member

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    Thanks Patrick, will tomorrow


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  13. avipet

    avipet Junior Member

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    Your conversation sounds like the topic I am needing to investigate on my 2006 Prius. Over the past 6 months I've had intermittent and now constant Check Engine warning lights. The code is P1121 (Coolant Flow control valve did not show a change in output voltage or the voltage changed slowly when commanded by the ELM to open or close, or following coolant recovery. Coolant Flow Control Valve Position Sensor Circuit stuck.) With this code, do you recommend replacing the connector pictured above? If yes, it it hard to replace?
     
  14. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Usually the valve would have to be replaced as it tends to stick in one position which causes the DTC to be logged.
     
  15. avipet

    avipet Junior Member

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    Is there a video or instructions on how to find the valve and replace it? If I want to buy one - what is it called?
     
  16. Patrick Wong

    Patrick Wong DIY Enthusiast

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    After you do the resistance checks, another test would be to apply 12V to terminals 1 and 2 and verify that the motor will move the valve from one position to the other. Also measure resistance from terminal 4 (which is the wiper arm of the variable resistor) to terminals 5 and 6 (which are the two ends of the variable resistor) and see if that measurement varies smoothly as the motor is moving.

    There are several strings about the engine coolant valve and how to replace it.

    I believe this is the correct valve but will leave it to you to verify the part number.

    Toyota Prius Valve assembly, water with bracket. Engine - 1667021010 | Roseville Toyota, Roseville CA
     
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  17. m.wynn

    m.wynn Senior Member

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    That is the correct part number as of this past July. I've purchased 2 of the 3-ways with a ~2.5 year spread and the part number was same for both.

    3-way valve, 12-29-2014 001.jpg 3-way valve, 7-20-18 001.jpg
     
  18. Raytheeagle

    Raytheeagle Senior Member

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    Good deal on the SLLC too:).

    Must know somebody at the parts counter(y).
     
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  19. m.wynn

    m.wynn Senior Member

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    Paul, try a quick MAF/TB cleaning for the rich code. Our '07 (~195k miles) throws it about every year or 18 months and this has been my "fix" several times over now. I've done a Techstream test-drive follow-up and watched fuel trims return to normal. Ymmv but it's been a quick and dirty for me. I use the CRC maf and throttle body/air-intake sprays, fwiw.
     
  20. avipet

    avipet Junior Member

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    Thank you very much for your help!!