Welding was done on the rear quarter and a HV charge was done for a few seconds and then shut off before disconnecting of the 12 volt battery and now I have these symptoms. 1 – Upon starting the 2001 Prius the engine horn beeps 1 time and the windshield wiper does 1 revolution and stops. The engine runs and fuel gage and ready light is on correctly. 2 - Center display is no longer bright and it is very dim. 3 – Driver airbag warning light stays on and will not shut off unless I shut engine off. 4 – Key fob no longer works the door locks. If the car is running the interior door lock button works on all the doors. No functions work with the key in the on position. I did have the triangle of death but when we charges up the 12 volt battery fully this warning light has not come back. All other functions work, radio the fan, heater, horn, wipers, ect. only when the car is running. All fuses have been visually tested and test light tested to be good. 12 volt rear battery is charged and only 6 months old. It was disconnected for over and an hour and reconnected and it made no difference in the symptoms. We got to where the ECU and HV ECM is located and have tested the ECU terminals to be 1.5 volts. We now need to know the procedure on how to test the terminals of the HV ECM and we need the pin out codes unless someone knows for sure which computer is bad. Also, Alldata says check voltage of ECM pins HTE+ & HTE -, but does not say what the voltage should be. And, it says to check for an open & short in harness of HTE+ & HTE - ECM & HTE+ & HTE - of HV ECU, but it does not say what I should see, an open or short. I'm leaning towards the HV, but don't want to easter egg & start replacing at random, could get expensive. Thanks.
Ok, you've got a situation here, and one priority would be to avoid making it worse. From the symptoms I would guess that your Body ECU (at least) is among those damaged. Diagnostic procedures involve either a Toyota-specific scantool, or a jumper wire following the alternate procedures in the factory service manual. You can get the FSM on paper from Helm, Inc. (helminc.com) or possibly from Toyota's Materials Distribution Center (the telephone number is in the back of your owners' manual), or online for a cheap subscription fee at techinfo.toyota.com. Given that you're having symptoms of unusual problems that might be extra tricky to diagnose (especially if more than one ECU turns out to be kaput), I would not recommend trying to go by other sources of repair information than the FSM. If you can stand it, I'd suggest taking a break to really study the diagnostic procedures in FSM volume 1 before doing much again with the car itself. Hope this helps, -Chap
Thanks Chap. I cannot locate the BCM in the car, do you know where it's located? There's not allot of info out there. I did swap the horn relay (it stay on after hitting the horn button) & swapped it with another same PN relay & it then stayed on constantly. I'm leaning towards BCM.
Don't give up, all the information you need (ecu locations, test procedures, color codes, pinouts) is available. It's just in the factory service manual and wiring diagrams, so if for some reason you don't look there, you might think there's not a lot of information: "available information" minus "factory service manuals" sometimes equals "not enough information". Sometimes for common stuff there is plenty of information in other sources, but if you've got an oddball problem, sometimes you need to look where the information is. If all you want is to find the body ecu (and even see a little of how it is built) then you might like the disassembly page that should be your first hit if you google for prius body ecu. Hope this helps, -Chap
AHA! I found the problem and fixed it. It was the 100 amp DC fuse. Usually a fuse breaks at the center so visually u can see it broken but this one broke at the corner edge so u could hardly see the problem. What a job changing that fuse - it is bolted in under the fuse block so the complete fuse block had to be undone and turned upside down to get at it. $7.50 cents for the fuse. I am so relieved. We put the fuse in and presto everything worked as it should except the gas gauge was blinking empty. I believe I read somewhere on this forum it will reset it self in time? Thanks to all who answered my call for help.
