P0A94 code DC to DC converter

do i need to update the version of techstream I am using?

 

Through pure luck and trying this too many times I was able to get the car on, with dash lights and a decent battery charge and I still cannot get techstream to go into active test mode on the one for inverter stop. I think there was another version of techstream. Any other thoughts?

 

Im using windows xp, 32 bit and TS version 15. Is there a better version that might be more functional?

 

It seems like others have had trouble doing active tests in Techstream. Can anyone guide me to a better version, or some further info on this?

 

Does anyone have any experience in successfully conducting an active test using a knock off version of techstream? Perhaps I should pay the $65 for a 2 day authorization to use Techstream from Toyota?

 

Can I get an opinion on this complicated question?

I have error code P0A94 with subcode 555. Im going to attach the troubleshooting guide that one of you gave me to make sure I'm doing this right and ask this question.

According to the first page of the attached I can just put the above code in and I'm moving on down that sheet to the next page. On the next page it's having me look up the DTC again and the subcode and plug that into the chart starting on line e.

P0A94-555 equals DC/DC converter malfunction.

When I go below that chart there is a yes or no arrow.

The "yes" arrow says "Go to DTC Chart (See page 05-440). Find a page number to proceed to its diagnostic troubleshooting flowchart.

The "no" arrow puts you through the diagnostics for the inverter, the motor, the generator, the transaxle and the hv ecu.

HERE'S THE ACTUAL QUESTION: Do I have a yes or a no to this question. If I have a yes Im supposed to get the diagnostic flow chart......but isn't this the diagnostic flow chart already? If it's a no, then I follow the chart to diagnose what this issue is?

Is there another diagnostic flow chart for P0A94-555?

 

Sorry, here's the file:

 

Yeah, that's what I thought too. (BTW, I cut the page down to 2 pages for this example, and I do have the rest of it.)

 

But if i have a yes at that point then can someone look this up for me: Go to DTC Chart (See page 05-440). Find a page number to proceed to its diagnostic troubleshooting flowchart for P0A94-555. If we are right that it's a yes, then the correct troubleshooting flowchart is the one I already have. (If there is something else there, then any help in getting a copy of that would be appreciated.)

 

Ok, cool Thanks for walking me through that.

In light of this here's what Im thinking. From the troubleshooting I was able to accomplish the only thing I actually eliminated was a bad transaxle.

I wasn't really able to get the diagnostics for the inverter, the motor, the generator, and the hv ecu done.

In my experience and reading on the internet it would seem to me that the order of likelihood of these issues is:

1. the inverter, most likely the problem (perhaps caused by the inverter coolant pump. (It was a hot day when this failure occurred.))
2. the hybrid vehicle ecu

3 and 4. The motor and generator. (there hasn't been any damage to the vehicle and this seems like it would be an issue more likely caused during an accident or something.)

Also, I can get a used inverter and an ECU for under $300, so Im thinking of replacing these and the coolant pump in the same order listed above. If it still doesn't work after that, I'll have to consider giving up the car. Parting it out, etc.


Do any of you have an opinion on my logic? advice on a better strategy assuming Im determined to go ahead on my own.


thanks for everyones help so far.

 

Success!!

I purchased a used inverter for around $250 that had some very mild assurances that it would work. I also purchased a used HV ECU for around 30 bucks and when they came in the mail and i had a few hours, I switched out the inverter. I didn't use the HV ECU....

I still need to give it a real test drive, put the windshield wipers back on and put away some tools but my car started up for the first time in several weeks with no warning lights and charged up the battery while I sat in the driveway for a few minutes.

I'll post again in a few days with a final status report. Thanks to everyone who helped with advice I really appreciate it.

john

 

One more problem. After this work was done and my car runs again and I did the final inverter coolant fill and bleed everything seems fine. I waited a day or two and I looked at the coolant and it was a bit low so I topped it off. I wondered if after the bleed of the coolant it had settled a bit or something. Then I waited a day or two and did the same (weird that it happened again.) and at that time I dropped the coolant cap on the ground and when I looked for it under the car..... I found coolant leaking.

To be clear, in the reservoir the coolant doesn't all run out, it sort of goes from being full to being low and then stops leaking....(at least when the engine isn't running.) I just drove it about 10 minutes and it was wet down below afterwards....leaking a bit, but not really lowering the level in the reservoir yet.

Im thinking that maybe it was leaking before and on that hot day when this all started there wasn't enough coolant to keep things cool and I fried the inverter.

I did replace the inverter with a used one. The refill reservoir/tank is the same one from before....I moved it from one inverter to the other. I did replace the inverter coolant pump.

The area that shows leakage seems to be located in the center of the engine when I look from below. So I'm thinking not the inverter coolant pump. I don't see leakage from the hoses that I removed from this system at or near the reservoir.


Im thinking there could be a crack in the inverter coolant fill tank/ reservoir, or maybe it's not on tight enough after I moved it over, or possibly the o ring on that bottom seal that I re-used was no longer good enough.



Is there some other place it could be leaking?


Thanks

 

To be clear, the inverter reservoir shows a little below the low fluid mark, no leakage, stable for days, drives fine for short drives... Then I add fluid to bring it up to the full line. Then I look below and it's pouring out. 20 min's later it's back to a little below the low fluid mark, no leakage, maybe a bit of dripping but slowing to nothing pretty rapidly


I cannot see a leak anywhere specific....

 

Is it safe to say that the inverter coolant reservoir is the highest place in that system? The fact that the coolant only leaks when filled to full and stops just a bit under the low fill mark indicates that it must be the reservoir cracked in the back somewhere that I cannot see it.

If it was the o ring at the bottom, it would leak out of the bottom of the reservoir until empty wouldn't it?