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

2006 Replaced Inverter, low power and bad mpg

Discussion in 'Gen 2 Prius Main Forum' started by Barry CLEMENTS, Oct 9, 2019.

  1. Barry CLEMENTS

    Barry CLEMENTS Junior Member

    Joined:
    Feb 22, 2019
    52
    9
    0
    Location:
    92129
    Vehicle:
    2006 Prius
    Model:
    N/A
    Red triangle appeared on a 90 degree day and I didn't make it home. After it came on, I checked the coolant pump and a smooth vibration could be palpated, so I continued the drive home since the car was running well. Bad decision. The car stopped in the middle of the expressway 5 miles from home. No power at all. Replaced the AM2 fuse, got power back but the car wouldn't start. Codes then, as now (after inverter replacement), are P0A08 and P0A09 and the coolant pump still humming . I replaced the inverter with a refurbished one and replaced the 12-volt with a new battery. Started fine but the Red Triangle was still there even after resetting ECUs and I could not get above 53mph on freeway and mpg was down to like 14mpg. I thought I got a bad inverter so I bought another one. Same result. 13.9 across 12v terminals and traction battery cells are all in the red and still surprisingly well balanced. Also, cruise control doesn't work but there are no associated codes. Techstream codes are P0A08-264 (DC/DC Converter Status Circuit) and P0A09-591 (DC/DC Converter Status Circuit Low Input). What's next?

    I should also mention there is no noise in the apparently very smooth operating transaxle. I also changed out the transaxle fluid while doing the rest (I also replaced the inverter/transaxle coolant pump since the unit had over 100K miles on it). Now I know that doesn't rule out an electrical issue in or en route to the transaxle, but it does seem to be operating well mechanically. I think this is a purely electrical issue. Just don't know where to start. Hoping somebody out there had the same issue and has a fix to go with it.

    Sometimes I pine for that ol' straight six.
     
    #1 Barry CLEMENTS, Oct 9, 2019
    Last edited: Oct 10, 2019
  2. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

    Joined:
    Feb 14, 2010
    6,035
    3,854
    0
    Location:
    Rocky Mountains
    Vehicle:
    2006 Prius
    Model:
    Three
    Did you check the fluid turbulence in the reservoir? Or just put your hand on the pump and feel it vibrate?

    If you blew AM2 it sounds like the pump might be bad. Large currents out into a system that shouldn't need can throw codes sometimes. It is normal to have to reset the codes manually after replacing a part, the car doesn't know you did it. But if they came back, then that's most likely not the cause. Unless you got unlucky and the junked inverter you put in also had the same problem.
     
    #2 2k1Toaster, Oct 9, 2019
    Raytheeagle likes this.
  3. Barry CLEMENTS

    Barry CLEMENTS Junior Member

    Joined:
    Feb 22, 2019
    52
    9
    0
    Location:
    92129
    Vehicle:
    2006 Prius
    Model:
    N/A
    Actually, since I had the inverter out, I replaced the inverter/transaxle coolant pump since this was the warranty unit with over 100,000 miles on it. And yes, the old pump worked as I opened the bleed valve in READY and it bled aggressively. It may be that both inverters are bad, but unlikely since they are both bad in the exact same way. That would be a cosmic joke, eh?
     
    #3 Barry CLEMENTS, Oct 10, 2019
    Last edited: Oct 10, 2019
  4. edthefox5

    edthefox5 Senior Member

    Joined:
    Jul 25, 2007
    10,096
    4,795
    0
    Location:
    Clearwater, Florida
    Vehicle:
    2007 Prius
    Model:
    Two
    I think 2ks point is don’t touch the pump as a test just open the coolant reservoir and see if the fluid is moving inside the reservoir.
    A healthy pump and correctly bled loop the fluid looks like it’s boiling it has such aggressive circulation.
    If the fluid is just sitting in the bottle the pump is not pumping no matter what it palpates.

    Also be aware if you have never personally changed the coolant in that loop it has never been changed. They don’t change it with the warranty pump replacement they just duckbill the hoses off and slide a new pump in.

    Step one on blown am2 pump and no start is check the 12 volt battery voltage at the front jump point.
    Not at the battery it does not matter what it measures at the battery it only matters what it measures at the front jump point. That front jump point bolt is bolting the main power cable from that 12 volt battery to the fuse box. Check with car off. Report back here.

    Step 2 is disconnect the pump plug and see if you have 12 volts there in Ready.

    Step 3 is check every fuse in the fuse boxes the black box under the hood and the fuse box next to left knee in cabin.
     
    #4 edthefox5, Oct 10, 2019
  5. Barry CLEMENTS

    Barry CLEMENTS Junior Member

    Joined:
    Feb 22, 2019
    52
    9
    0
    Location:
    92129
    Vehicle:
    2006 Prius
    Model:
    N/A
    Thank you. I will definitely check those. The coolant was changed by me about 60k mies ago. But how would a bad pump circuit cause the symptoms I am experiencing? I understand those issues would cause the red triangle, but not the low power and crap mpg.
     
    #5 Barry CLEMENTS, Oct 10, 2019
    Last edited: Oct 10, 2019
  6. edthefox5

    edthefox5 Senior Member

    Joined:
    Jul 25, 2007
    10,096
    4,795
    0
    Location:
    Clearwater, Florida
    Vehicle:
    2007 Prius
    Model:
    Two
    I don’t think you mentioned the miles on the car. Doesn’t matter much given the age of the car
    As far as the hybrid battery is concerned. But hybrid battery issues are very common here
    If not the #1 post as all g2s are at that vintage.

    If the battery is tanking to one purple bar all the time and takes a long time to get one or two blue bars in it
    That’s like stage one of battery failure. Poor mileage and no power too.

    Ever hear the fan in the back seat come on.? That’s the battery over heating. You have techstream look at the battery.
     
    #6 edthefox5, Oct 10, 2019
(You must log in or sign up to post here.)