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P0A78 - 282 and P0A94 - 548

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by FantasticalMagicOne, Nov 28, 2019.

  1. FantasticalMagicOne

    FantasticalMagicOne Active Member

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    P0A78 - 282 Motor "A" Inverter Performance
    upload_2019-11-28_19-16-41.png
    P0A94-548 DC/DC Converter Performance
    upload_2019-11-28_19-18-2.png

    Front End Collision last night, and it seemed like it was just cosmetic (front bumper cover). Had to make a few stops (3) then home, approx 25 miles total. Leave for dinner tonight, and 2 miles down the hill, the hybrid warning lights came on, my stomach sank (inverter). Very slowly drove it home, the longer way as I didn't want to turn around and attempt a steep hill, plus it was better lit with lots of places to pull over. The MFD showed that ICE wasn't powering the battery while it was running (inverter). Made it to the driveway, brought the ham inside (oh, I've got 17 people currently waiting for food), and the laptop outside. This is what I was met with. The Inverter, and possibly the transaxle (surprise!). I know that there are a few things that I can check that would be reasonable to fix, but let's face it, that'd be a HUGE hail mary, and I'm pretty sure that I don't have a car. Happy Thanksgiving!
     
  2. Elektroingenieur

    Elektroingenieur Senior Member

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    The Repair Manual (more info) procedures for both of the diagnostic trouble codes you mentioned list “Wire harness or connector” as the most likely trouble area—though there are other possibilities—and they suggest specific connectors to check first for looseness or poor contact, at the hybrid vehicle control ECU (H14, H15, H16, and H17) and at the inverter (I9 and I10). With a car that had just been in a collision, I’d start there, taking the necessary precautions for high voltage, of course.
     
  3. FantasticalMagicOne

    FantasticalMagicOne Active Member

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    Thank you, I saw that and intend to check when I have daylight, but, the other common trouble area is the "power module intelligent transistor set," and that's more bad news. I'm going for the hail mary, but I'm not hopeful.
     
  4. ChapmanF

    ChapmanF Senior Member

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    A Gen 2, right? Some of those electrical connections to the tranny (low-voltage ones) are pretty exposed in front, where a bit of damage in a front collision wouldn't be surprising.

    I've seen a Gen 2 rebuilt from a front collision, with several of those tranny circuits spliced back together with telecom splices. That's not the technique I would recommend—I would lean instead toward Toyota's specified repair splices and tooling—but it would not be a hard repair either way.

    I get that the troubleshooting instructions also mention other possible culprits, like the power module, but that's because they have to be written to over all the possibilities. If you happen to know the car has recently been clocked on the nose, there's probably no need to sweat the more dire hidden possibilities before you've looked into the obvious exposed ones.
     
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  5. FantasticalMagicOne

    FantasticalMagicOne Active Member

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    Update:

    I checked the connectors in the inverter, but not the HV control ECU as the weather hasn't been kind enough for such a time consuming task. I have been thinking over what I should do about this, and it occurred to me, that I've had hybrid codes thrown and the problem was ICE related.

    Prior to the accident, I was concerned about the noise level of the ICE, and that the oil dip stick read higher on one side than the other. For the latter issue, I had removed and cleaned the dipstick and left it out over night and checked the oil the following morning to find that it was very low. I was in a bit of a hurry so I grabbed the oil I had on hand left from the last oil change (1.5qt), but in my haste I didn't use a funnel and consequently spilled oil over the side.

    For the former, I had intended to check the throttle body and MAF, but didn't get to it before a front end collision took place. I took a look when the weather broke, and sure enough I found oil in the throttle body. I had a PCV valve on hand from last year during my sensor debacle, so I changed it. When I did that, I saw a fair amount of oil on the cylinder head where the fuel injectors are; this car is toast. I wouldn't have bothered putting it back together had I not had full coverage on it. Probably a bad idea to leave the car torn apart if I had to call in a claim. Then I remembered, I didn't use a funnel when I added oil a week or so prior, and consequently spilled it over the side (doh!). So I ended up going through the extraordinarily fun task of taking care of that mess. I removed the injectors in order to clean the head, and figured I'd test/clean them while they were out. Of course, as I was removing the pipe clamp on the fuel line, I dropped it and it fell into the abyss (ugh!). Due to lack of transportation and more inclement weather, it took me about a week to obtain the supplies I needed. The injectors tested fine, and with 4 new seal kits, I took on the delicate task of reinstalling them. It didn't go well, when I started the car, it began bucking and was extremely loud, the check engine light came on, as did the triangle of death, and the hybrid system warning light, and there was gasoline spewing out of the injectors. After ruining a few o-rings, obtaining new seal kits, and repeating the process much slower than before, I cleaned the MAF and throttle body, checked the air box filter, and reassembled the car. Moment of truth, I took a deep breath, started the car, made sure fuel wasn't spewing out of the injectors, and it was a success! I turned off the car to set up techstream, and when I turned it back on, it attempted to start then failed to do so; twice. I took a deep breath, and accepted defeat, then remembered the pipe clamp. This particular clamp, part #2384121050, can only be obtained from Toyota, so I called up the local stealership and ordered it. I picked it up, filled my gas can, disassembled/reassembled everything (again), put gas in the tank and started it again. It should be noted that when you work with the fuel injectors, you don't put the car in "ready" right away, put the car in IG-ON and leave it there for a bit. A lot of work on something that wasn't indicated as a problem when I went over the results of the health check. The car started, it ran a bit rough, and was still loud. I decided to put it in maintenance mode and let it run for awhile. No lights came on the dash, and there were no codes thrown. I know it needs to be driven for awhile after the computers are reset (the 12v had been disconnected through most of this), so I waited to report any of this. I've driven about 50 miles since then, both highway and city driving. No lights have returned, and no codes have been thrown.

    That being said, the car is intermittently loud when it idles, has difficulty accelerating and is very loud when it does. You can feel it fighting to get up to speed, but once it reaches the desired speed, it runs fine. So that's the problem I'm currently facing.

    In addition to the above information, my '08 has 179,300 miles on it, and the HV battery was recently reconditioned. Since last October the following have been replaced: catalytic converter, muffler, 02 sensor, A/F sensor, 12V, serpentine belt, air filter, cabin air filter, tires, water pump, thermostat, coolant pump, and both cooling systems received new coolant. I also changed the transaxle fluid. The iridium spark plugs were replaced, at the dealership, last May at around 157k. Changed the oil and filter, but definitely needs to be done again (very soon).

    The oil level is currently fine, and the coolant tank next to the converter has turbulence when the car is on. Ideas?
     
  6. Almuthafri

    Almuthafri Junior Member

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    I have highlander and I got this code p0A78 .what am i going to do by myself.i test the car on techstream to get that