inverter testing and replacement

[Patrick Wong]

Originally Posted by andyprius

...So, Where is the inverter, what is it's physical size, is it a stand alone box, what is its output voltage and frequency and last can it's output be seen on a OScope with only 12VDC feeding it ( on a bench). ty

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...

[GinnyErns]

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

[Patrick Wong]

Originally Posted by GinnyErns

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.

[lmahaj]

I just got a scanner, cleared the codes, and now it runs (I ran it about five minutes) like there is nothing wrong, with no MILs or error codes. I don't think unplugging the negative terminal necessarily clears the codes (I've experienced this on a different car also). I checked the aux battery voltage when 'off' (~12V) and 'ready' (~14V). I still don't hear the inverter coolant pump running (I also checked voltage to that and it gets 14V when ready). I'm going to order a new pump ($150) and replace it. Then drive it till the computer tells me the inverter is not working. Considering that the aux battery is getting 14V, and the main battery (is this the traction battery? and I don't see any "SOC gauge" anywhere) is accelerating fine from a stop (no turtle icon), I am hopeful it is just the pump.

To answer the error icon question, it was only the car with ! symbol.

Any idea how long I would need to drive before the code gets set again if the pump is not running?

[Patrick Wong]

Originally Posted by lmahaj

I just got a scanner, cleared the codes, and now it runs (I ran it about five minutes) like there is nothing wrong, with no MILs or error codes. I don't think unplugging the negative terminal necessarily clears the codes (I've experienced this on a different car also). I checked the aux battery voltage when 'off' (~12V) and 'ready' (~14V). I still don't hear the inverter coolant pump running (I also checked voltage to that and it gets 14V when ready). I'm going to order a new pump ($150) and replace it. Then drive it till the computer tells me the inverter is not working. Considering that the aux battery is getting 14V, and the main battery (is this the traction battery? and I don't see any "SOC gauge" anywhere) is accelerating fine from a stop (no turtle icon), I am hopeful it is just the pump.

To answer the error icon question, it was only the car with ! symbol.

Any idea how long I would need to drive before the code gets set again if the pump is not running?

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.

[tochatihu]

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!

[andyprius]

Originally Posted by Patrick Wong

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...

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.

[lmahaj]

update: replaced the coolant pump and bled system. Has been running for 400+ miles without any problems.

[lmahaj]

update: 800+ miles since coolant pump replacement ( $150 part, 3 hours labor (me = free, sales = $500), runs fine. Getting 45 mpg, driving mostly short routes (2-5 mi).