inverter testing and replacement

Hi Andy,

The inverter is located in the engine compartment on the driver's side, and is the large assembly that has a shiny aluminum cover with the Toyota Hybrid System decal. This also contains the DC/DC converter.

The inverter cannot be easily benchtested because the input is the high voltage 200+VDC from the traction battery. The outputs are high voltage three-phase AC for the two MGs, high voltage for the air conditioning compressor, as well as 12VDC output for the DC bus. The inverter is receiving control signals from the hybrid vehicle ECU to decide voltage and frequency for the AC provided to the MGs and the AC compressor. The inverter is watercooled, so it can be run only for brief periods without such cooling in place.

Given the above, I would say that it would be quite an endeavor to successfully rig up an inverter testbed outside the vehicle. Hence the easiest (and best, IMO) solution for a failed inverter is just to buy a salvage one for ~$400 rather than mess around trying to effect a repair...

 

Hi Patrick
When a used inverter is purchased...does that include the coolant chamber....
when inverters are replaced...do they have to bleed the coolant too...
Does a used inverter nullify the warranty?
Thanks Ginny

 

Hi Ginny,

Usually the used inverter will include the plastic coolant tank mounted on the side. Used inverters sold on eBay typically have photos that show you exactly what is included.

Yes, when the inverter is replaced it is necessary to drain and replace the inverter/transaxle coolant. I believe you had previously said that the quoted labor for the entire job is 8 hours?

If you install a used inverter, and this causes failure of a related component (like the transaxle) then such damage would not be covered by the hybrid warranty.

 

What DTCs were displayed by your scanner, before you reset the codes?

The traction (aka main) battery state of charge gauge is displayed on the MFD, when you select the screen that shows power flows between the motor and battery and wheels. The battery icon will fill up with the green (or perhaps blue, I forget which) color, as the SOC increases.

You are on the right track with your repair plan. If the inverter coolant pump is the only problem, you would have to drive a sufficient distance for the inverter to overheat (perhaps 15 or 20 miles), which depends upon the ambient temp in your area and your speed.

 

Based on my experience bleeding air after an inverter coolant change. When the fluid is not circulating effectively, the electronics heat very rapidly. I would like to suggest 'on' cycles of 5 minutes or less, interspersed by 20-minute 'cooldowns' with everything off.

If you could get your hands on a device capable of reporting the inverter temperatures (the Graham Davies Ecrostech Miniscanner may be the only option for your 2003?), it would be better than driving until the error code appears. Remove the cover from the inverter and find out what gets hot in there, and how soon? I never took the shiny cover off so I can't advise there.

Good luck!

 

Thanks for your usual VERY complete answer, after looking at hobbitts picture of the inverter I can see that there is much more to it, and a lot of very advanced electronics. At least I know where it is now! Incidentally I attempted to contact Tom Scott Dealership in Idaho, thru Email and as is very often the case, the Email system does not work.

 

I hope someone can respond to this. I have been getting Code P3125 for two years, typically if you wait 30 mins or so, the car starts and functions normally, typically for about 2K miles. Long story short, dealer has made Thousand of dollars of repairs, still have same problem. Changed: circulation pump (2x), Inverter: old one is now back on the car. I strongly suspect that the dealer did not bleed it correctly at each repair.

1. I suspect the ECU (ECM?) part # 89661-47054 (there are other numbers for this, this is the number I would like to replace it with)

2. I need to bench test a (new) inverter the dealer put in, and then said it was bad. I suspect it is good. Any help?

3. at this point, I do not trust the dealer, and it is the only Prius repair available here (except me), and I am learning. I do not want to give up on the prius yet (88K miles)

Any advise?

 

If DTC 3125 is the only logged code then I doubt the engine ECU is the problem. It may be possible that the hybrid vehicle ECU is contributing to the problem.

I got rid of my Classic repair manuals when I sold my 2001. If you can get the three digit info code that accompanied DTC 3125 that would provide more info about the root cause. techinfo.toyota.com is a subscription website where you can download repair manual info including how to interpret the DTC and info codes.

Regarding inverter testing, really the only practical way to test in the field is on another Prius. This is especially true since you say the problem is not solid, but instead takes some time to manifest itself. So you'll need to make a good friend who is willing to let you experiment on his/her older Prius. Good luck (you'll need it.)

 

To Wong or anyone,

I just bought an 02 prius with 176k and can only driven about 3 minutes with about 30mph then code p3125 appeared then the car slow down very quick to almost not moving. I parked the car and engine cut off in a minute after that. Is there any way to know if it is a pump problem or inverter or hv ecm? Thanks

 

Eric8, I am very sure part # 89661-47054 is engine computer. That is different with inverter computer or HV ECU with part # something like 89981-47040.

 

Re: inverter testing and replacementhtreead

This is quite an old thread, but I will give it a go, what is the condition of the High Voltage Battery. Charge level is either pink, blue (50) or green If the car goes in ready, do a force charge and charge it to green bars. That should take 1-2 min Next, insure your 12 V Battery is good, either with a multi-meter or the 12V diagnostic self check. If unfamilier with terms, look them up on google. First and foremost, look at the liquid at top of coolant container for inverter, it should be bubbling, you can see it with the cover off. If liquid is very low, not bubbling or the inverter very hot to the touch, shut off ign. immediately. Should everything be good up to this point, do not shut off the ignition, keep the car charging both HV and 12V. Run for 8 hours OR at least til you have determined that all charges are good. Especially the 12V Battery. Naturally make sure 12V contacts are clean and tight. Post back and let us know your progress. :cheer2:

 

Re: inverter testing and replacementhtreead

Thanks for your response. 12V battery needs to jump start. I will charge it or change a different one. no bubble in the inverter coolant. I am thinking to change the coolant pump first to see what happen. I do have all the used parts for the prius but try to find the way to do it right. Will let you and the forum know.

 

.. some wrote >. "Also, while test driving, for a very short distance, the throttle response was very strange, lagging and not going to full power. Also the ICE would not shut off as if it was trying to charge the battery .. "

this is exactly what is happening with my 2005 Prius .. today for the first time .. my daughter was driving with the pump not working .. I changed the pump today and then tried to drive it .. the power was gone and could only drive uphill at 20 mph ..

And what is it ?

 

I'm working on inverter replacement too. if anyone has the docs for a gen2 it would be appreciated

 

Can you tell me about resistance of the 12 volt inverter pump. I Think I’m getting a zero on the old one and 12 ohms on Th e new one. Zero indication of bad pump correct?

 

Yes, that shows the motor winding has a short. Replace the AM2 fuse if blown.

 

Thank you sir. Lol. Bought this car a used 2006 for parts thinking it had mucho electronic problems (appears mice were fond of it after 2 years) but seems that the 12 volt pump mentioned was the culprit. New one and that am2 fuse and viola. One issue is the instrument panel came on with a few tests, but now nothing....... but all else works, ice, hybrid system, Climate, mfd. Now please overlook my poor punctuation!