1. Attachments are working again! Check out this thread for more details and to report any other bugs.

CEL Hell - 2007 Gen 2 Trials and Tribulations

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Gdogrun, Mar 31, 2019.

  1. Gdogrun

    Gdogrun Junior Member

    Joined:
    Feb 10, 2019
    8
    2
    0
    Location:
    Janesville, WI
    Vehicle:
    2007 Prius
    Model:
    I
    Hello Fellow Gen 2 Prius Owners:

    I bought a 2007 Prius last December as a daily commuter. I drive about 100 miles per day, so I wanted the high mpg and reliability that the Prius has become known for. It had 150,000 miles on it when I got it, and I have to say I've been pleasantly surprised at how much I like it, and it's versatility at everyday tasks. BUT...

    Within the first day of getting it, I started seeing the CEL come on, and it's been on/off ever since even after a significant amount of work from me, and several trips to the dealer. See my timeline below of the codes and what's been done:


    December 28, 2018
    P2601
    Dealer said it was heater control valve (HVAC), replaced it


    Jan 13, 2019
    P1116 - Coolant Temperature Circuit Stack
    Read some posts here and also watched some videos online
    Replaced inverter coolant pump - DIY
    Reset the CEL

    Jan 18, 2019
    CEL, light came on - P2601
    Took it to dealer on Jan 25, 2019
    They replaced the CHS tank pump - ~$400
    Reset the CEL
    Light stayed off for a few weeks


    Feb 15, 2019
    CEL light came on
    P1116 - Coolant Temp sensor/coolant storage tank
    Dealer wanted to replace CHS storage tank, estimate $1675
    Declined to do it at that time
    I reset the CEL light
    Stayed off for a couple of weeks


    March 4, 2019
    CEL light came back on
    P2601
    Coolant Pump Performance Control Circuit Range

    TODAY - still driving with the CEL on, and code P2601 is what the system is throwing when I check it. The car seems to drive OK, no signs of trouble with it. I do hear the pump run right after I shut the car off, and again when I start it.

    My question is, do I really need to replace the CHS coolant tank and sensor like the dealer said? I've done basically everything else (heater control valve, inverter coolant pump, and CHS tank pump). I just have a hard time believing I had to replace every major part of the system and the car really doesn't have that many miles in the scheme of things.

    If I do need to replace the CHS coolant tank/sensor, should tackle it myself, or is this one best left to the dealer or other trusted shop? I did the inverter coolant pump myself, which involved tearing a big part of the front bumper apart to get to it, and it wasn't that bad.

    Let me know your thoughts, experiences, and two cents worth if you have time to read this somewhat long-winded first post. Thank you.
     
  2. dolj

    dolj Senior Member

    Joined:
    May 14, 2012
    7,447
    3,750
    0
    Location:
    Wellington, New Zealand
    Vehicle:
    2007 Prius
    Model:
    N/A
    Sounds like they are replacing everything except the most likely candidate – the three-way coolant control valve – if I'm reading it right.
     
    Gdogrun likes this.
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    18,198
    6,461
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    Please provide the part number and description of the valve replaced on December 28.
     
    Gdogrun likes this.
  4. Gdogrun

    Gdogrun Junior Member

    Joined:
    Feb 10, 2019
    8
    2
    0
    Location:
    Janesville, WI
    Vehicle:
    2007 Prius
    Model:
    I
    On December 28, they replaced the 3-way control valve. Dorman 601-021 (replacement part from Amazon). It was brand new.
     
  5. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    18,198
    6,461
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    Does that mean a non-Toyota dealer did the work? I would be very surprised if a Toyota dealer used aftermarket parts. I would also question whether the valve is working properly.

    That would be more likely than the likelihood of needing a new canister UNLESS the canister had been hit in an accident.
     
    edthefox5 likes this.
  6. Gdogrun

    Gdogrun Junior Member

    Joined:
    Feb 10, 2019
    8
    2
    0
    Location:
    Janesville, WI
    Vehicle:
    2007 Prius
    Model:
    I
    Yes, a non-Toyota dealer did the work. So you recommend checking the valve they put in to see if connections are correct? I suppose it's possible they installed it wrong. The person doing the work was not at all familar with Prius, as I found out when I picked it up after repairs.
     
  7. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    18,198
    6,461
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    donbright and Gdogrun like this.
  8. Gdogrun

    Gdogrun Junior Member

    Joined:
    Feb 10, 2019
    8
    2
    0
    Location:
    Janesville, WI
    Vehicle:
    2007 Prius
    Model:
    I
    Wow, that looks pretty involved. But I agree that's a better option to start with than just replacing the whole chs tank without eliminating all other variables first. I will give it shot this weekend. Thanks!
     
  9. Gdogrun

    Gdogrun Junior Member

    Joined:
    Feb 10, 2019
    8
    2
    0
    Location:
    Janesville, WI
    Vehicle:
    2007 Prius
    Model:
    I
    Hi Patrick. Quick update, I actually haven't tried to drain coolant and replace yet, per your posts #22 and #42 from previous thread. When I do, I am wondering if I need to bleed the system using the bleeder valve located on the right side of the engine compartment. Is this all part of the coolant system, or is there a separate system for the inverter coolant? Thanks for your help.
     
  10. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    18,198
    6,461
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    1. My idea of left and right is with respect to being at the rear of the car and facing forward. Hence left is the same as the driver side for North American vehicles.
    2. There is a bleed valve near the inverter which is for the inverter coolant loop.
    3. There is a bleed valve on top of the radiator which is for the engine coolant loop.
    4. As you have probably figured out by now, the two coolant loops are separate.
     
  11. exstudent

    exstudent Senior Member

    Joined:
    Jul 11, 2009
    2,207
    897
    0
    Location:
    Torrance, CA
    Vehicle:
    2007 Prius
    This was problem #1, which resulted in subsequent problems and premature replacement of Inverter pump.
    I vote AIR is still in the ICE cooling loop, which resulted in P1116.

    As Patrick pointed out in Post #10, there are TWO independent cooling loops on the Gen2 Prius: ICE and Inverter loop.
    ICE has TWO bleeder ports. Inverter loop has ONE bleeder port.
    upload_2019-4-29_18-6-37.jpeg
     
  12. Gdogrun

    Gdogrun Junior Member

    Joined:
    Feb 10, 2019
    8
    2
    0
    Location:
    Janesville, WI
    Vehicle:
    2007 Prius
    Model:
    I

    Hey Patrick, it's now several months later and CEL has never stayed off. Car is running fine in my opinion. Now the latest code being thrown is P1121. A lot of people on this forum have say that's the three way control valve. That was just replaced when I first got the car back in December/January.

    I tried checking for air in the lines today, cycling the CHS pump several times for 30 seconds while adding fluid in through the radiator cap. I didn't see any bubbles and fluid did not go down at all. So, I am assuming there is no air in the lines. This would make sense because the dealer replaced all coolant when they put in the new CHS pump.

    Any ideas for what to try next? Thanks for all your suggestions thus far.
     
  13. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    18,198
    6,461
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    I would replace the engine coolant valve (the one that you believe had previously been replaced.)

    If you have Toyota Techstream (Mini VCI) it is possible to perform an active test where you can move the valve to each of three positions, then measure voltage at the ECM wiring harness connector between pins WBAD (pin 20 of connector D) and E2 (pin 28 of connector A). E2 should be connected to body ground.

    The measured voltage should be 2.5V / 3.5V / 4.5V depending upon whether position VLV3 / VLV 4 / VLV 5 is selected.

    If you are able to confirm those voltages then the valve is fine. The next step is to look for coolant system clogs. If none are found then the ECM would need to be replaced.
     
    #13 Patrick Wong, Jul 28, 2019
    Last edited: Jul 28, 2019
    Gdogrun likes this.
  14. Gdogrun

    Gdogrun Junior Member

    Joined:
    Feb 10, 2019
    8
    2
    0
    Location:
    Janesville, WI
    Vehicle:
    2007 Prius
    Model:
    I

    Thanks, Patrick. Is it possible that the coolant control valve was installed wrong in the first place, meaning they switched up a coouple of the hoses coming into it? I looked and tried to follow where they went, but it's tough to see. Would the car even be able to run right if that happened? I had a former Toyota Technician tell me I should check that. Have you ever heard of that happening? See the below exlpanation from the tech:

    "1. Check the position of the hoses; the hose out of the bottom goes to the coolant heat storage tank. The hose in the middle goes to the engine and connects to the cylinder head and the top hose goes to the heater water pump and then to the heater core. The top 2 hoses are easy to mix up."

    The bottom hose looks like it does indeed go to the CHS tank, but I can't see for sure on the other two.
     
  15. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    18,198
    6,461
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    If the hose connections were switched then the cabin heater might not function correctly. There would be no noticeable difference regarding engine performance.

    If you are going to DIY then you will need to be able to see the valve. Remove the driver's side black plastic engine undercover. If you can't see the valve from under the car, then remove the inverter and whatever else is required to gain access to the valve so you can see what is going on. Good luck.
     
    #16 Patrick Wong, Jul 31, 2019
    Last edited: Jul 31, 2019
    Gdogrun likes this.
  16. Skibob

    Skibob Senior Member

    Joined:
    Sep 14, 2018
    2,912
    1,494
    0
    Location:
    Northern California
    Vehicle:
    2006 Prius
    Model:
    N/A
    There are post here of those hoses being reversed. If I remember the car will still run but odd things happen
     
    Gdogrun likes this.
  17. Gdogrun

    Gdogrun Junior Member

    Joined:
    Feb 10, 2019
    8
    2
    0
    Location:
    Janesville, WI
    Vehicle:
    2007 Prius
    Model:
    I
    UPDATE: Around Sept 15, I installed a new three way coolant control valve (OEM Toyota, not aftermarket). I also then refilled the coolant via the radiator, running the CHS pump via the relay for 15-20 seconds at a time. The install process was about 2 hours due to the tight area and the spring hose clamps. The bleeding process was about an hour. I then re-set the check engine light, and so far so good. It's been almost two weeks and the light did not come back on yet. Thanks everyone for their comments and help. This was a bit out of my comfort zone (que the ominous music, anquished facial expressions, and expletives while coolant was leaking out of the car and I struggled with those darn hose clamps), but in the end I feel pretty good about having completed the repair myself, and solved an issue that wasn't fixed by multiple trips to the local Toyota dealer.
     
    SFO and Skibob like this.
  18. TMR-JWAP

    TMR-JWAP Senior Member

    Joined:
    Aug 12, 2016
    6,058
    5,783
    0
    Location:
    Columbia, SC
    Vehicle:
    2007 Prius
    Model:
    Touring
    I'm curious about replacing the 3 way valve. Every time I replace an Inverter Cooling Water Pump, I have to unbolt the 3 way valve to remove the old ICW pump/bracket assembly. It seems to me it would be easiest to replace the 3 way valve by just removing the driverside headlight. It looks to have tons of access room. Has anyone done it this way? Did you run into any unforeseen problems?

    On a side note...I know its easier to just unbolt the new ICW pump from the new baseplate and then install the new pump onto the old base. I prefer to install the complete assembly that comes in the box. It eliminates any questions about why the old base plate is still in the car and it only adds 10 minutes to the job.
     
  19. pasadena_commut

    pasadena_commut Senior Member

    Joined:
    May 2, 2019
    1,329
    404
    0
    Location:
    Southern California
    Vehicle:
    2007 Prius
    Model:
    N/A
    Replaced an inverter pump that way last weekend and my recollection is that the 3 way valve is much lower down in the car than that pump. It is below the plane defined by the bottom of the headlight. It may be more accessible via that route than up from the bottom of the car, but it isn't right out in the open once the headlight is out.

    On the other side of that coin, when has that simple metal plate ever failed? So why waste time on it if there is nothing wrong with it? OK, I can think of one answer - if you can unbolt the plate with the pump on it faster than undoing the three bolts holding the pump to the plate. But you said it adds 10 minutes to the job, so, no.