Hi all its my first post here. I recently bought a used SALVAGED 2004 Prius with 45k miles on it. It looks and runs great except for that the previus owner never told us that it had an electrical problem that caused it not to start. It has done this to me on couple times now maybe someone can give me some advice to whats going on Here's what happens: I go to start it press the brake and hit the on button and the electronics power up. MFD powers up, the status screen goes on and but the hybrid battery has no bars. The CHECK ENGINE LIGHT, VSC, and little exclamation point lights (not the huge triangle of death) are illuminated on the dash. No Ready light and where all the gears are in the shift indicator the boxes are all flashing at once. The cooling fan in the engine bay is also running. We took it to the dealer and they said they've seen the car before and they recommended changing the HV harness and ECU, $5000 worth of repairs! The previus owner declined to fix it. Unfortuantely its salvaged so no warranty. To me it sounds like some sensor or ecu is failing. A little more info: The problem seems to be intermittent it happened two times then we drove it 500 miles and no problem, then it happened again recently. It seems to do this when its cold or somewhat humid out. I don't think its the battery also because the battery has plenty of voltage I tried jumping with one of those emergency jumper boxes (but it voltage is low). I'm thinking of trying to jump with a car next time or take to it to a shop that specializes in hybrids.
I also forgot to mention it eventually starts up with check engine light that disappears after the 3rd start up. Usually it'll start after an hour or sitting, but it really sux when it doesn't =(
Is the 12 volt battery the original? Has the 12 volt battery been checked. A weak 12v battery will do strange things when powering up the car.
I've measured the voltage and it puts out like 12.7 Volts when it working good that is. I tried jumping it with a weak jumper battery box so the battery isn't totally out of the question.
Just a little update I tried jumping it this morning it wasn't working again -_- and I jumped it using a big pick up truck and no dice. Tried it a couple more times and still the same result soo... I think I can definately rule out the 12V battery. After it warmed up (couple hours) I drove it to the dealership today to have them see if they've done the brake signal recall on the car and they said that there are no outstanding recalls on the vehicle so maybe it was done. Too bad I asked if they charged to check CEL codes and they did so I said I'll pass.
If you want to verify the diagnosis of the "HV harness and ECU" (this probably means the high voltage battery cables between the traction battery and the inverter, and the battery ECU), then you'll need to determine what DTC have been logged. My guess is that you have DTC P0AA6, Hybrid Battery Voltage System Isolation Fault, where there is a voltage leak between the traction battery terminals and ground. If the diagnosis is correct, then you should be able to repair the problem for substantially less if you obtain and install salvage parts. Good luck.
Are there any visible repairs to the engine harness? You should really go over the engine harness checking for damage. I would also check the engine bay grounds on both fender wells. If they had to paint under the hood the grounds could not be making a good connection.
Sometimes the auto repair shops will read out the codes for free. Always worth askin'. With the car off, can you twist the throttle plate easily? Bob Wilson
Yay the problem was finally fixed. I took it to Luscious Garage in San Francisco and they were able to fix the problem. Luckily it wasn't as bad as the dealer pointed it out to be. Apparently when the car got into an accident they took some of the components apart in that area of the car to fix the body, particularly where the fuse box was. One of the relay connectors that was going to a lot of other electrical components and the HV ecu had a bent pin when the people who fixed the car put it together. This caused the connector to not properly seat which would intermittently open the circuit. I'm glad I took it Lucious Garage, Carolyn the tech that was working on my car did a really good job =) She definately knows her way around the Prius. I highly recommend the shop to other hybrid owners who need work on their hybrids.