Gen 3 - J0V Recall - Bad MPG - ECU Swap

Toyota’s engineers have determined that software changes are necessary to prevent damage to the transistors in the inverter with converter assembly, and to prevent sudden and unexpected loss of motive power in certain non-normal scenarios. Their company believes so firmly in the need to apply these countermeasures that it has accepted the public embarrassment and adverse publicity of a series of safety recalls. (See Toyota’s defect information reports to NHTSA of February 12, 2014, October 4, 2018, and June 24, 2020.)

In this situation, I could only advise you to use the latest software from Toyota. Assuming, just for the sake of argument, that there has been a loss of fuel economy, and that there is no other cause, consider this the price of operating the hybrid system within the limits that are needed to ensure its durability and safety.

 

The beauty of the USA is that everyone gets to make their own decisions. From his posts in this thread, the OP clearly understands the situation the software upgrade is designed to address. He made a big boy decision that that situation is so unlikely that a 33% increase in day-to-day MPG was worth it. You don't have to make the same decision, but it is a reasoned decision.

Mostly, I just hope the OP circles back and reports what he finds out. And with his Toyota insider background, a few more posts in various threads wouldn't be bad either!

 

... disregarding the likely misattribution of the MPG change.

 

This is great original post and something I've been thinking a lot about. I see very little upside to taking my Gen 3 Prius to a Toyota Dealer to have them tinker with a car that runs perfectly and is "out of warranty". It seems that Toyota was forced to develop a software patch to remedy a potential safety issue. The testing and engineering that went into this "fix" leans heavily toward reducing Toyota's liability, and not into my well-being or the longevity of my vehicle.

The probability of my having an inverter problem doesn't appear to be high enough to justify exposing myself to a stealership and all of the revenue generating opportunities that this "fix" may create.

 

So far, my experience with my local dealership is whenever I go in for a firmware update of any ECU, whether under a recall or a TSB, I stand at the counter and tell them that's what I'd like them to do, they do that, and I drive the car away.

If you feel like being even more explicit and saying "by the way, I'm not interested in anything else", that probably works too.

 

I'm more concerned about the update itself. In my documentation from Toyota they say, "Toyota has received some reports where the (IPM) Intelligent Power Module may fail". While serious for Toyota from a liability standpoint, it doesn't feel like it carries much owner risk for me.

Anytime a manufacturer needs to update my firmware to address a liability issue, I end up running slower and less efficiently. I haven't done a single update on my 2015 since I bought it.

 

The J0V firmware fix is to change the reaction of the power management control ECU in a particular case where an IPM fails while driving. The reaction you would like is a reduced-power limp mode to get you safely out of traffic. The reaction without the J0V patch is an instant power-off.

This is not the kind of change that does much to your everyday driving experience, unless you're in the habit of frying IPMs right and left.

 

Then what happens when you get in a accumulative update situation and every update is uploaded to the car including the one that lowers your mpgs?

 

Which dealership were you working for? Just curious. I was a trainer with Toyota corporate for 7 years and joined a dealership group a few years ago.


iPhone ?

 

What was the outcome of the ECU swap?
I am having the same issue with my 2012 Prius. Though I was having MPG issues before the software update.

Thanks,

 

I would like to know the outcome of this idea also.

I know ever since I got the J0V update the power to the wheels was weaker and the engine turns on sooner now from a stop.

Im lucky I get good mpg now but if this could be done, then I would want to do this for the simple fact that my prius was using power to the wheels from the HV battery more than it is now, so it is using more engine power now.

That was way back when I had an old refurbished HV battery with modules older than my car and there was great torque from it then but after that update, I noticed right away the power was reduced.

Now I have a fresh engine, cat and exhaust and I can see the engine coming on too soon.

Plan would be get an updated 2015 Inverter and then source the ECU without the J0V update for best outcome.

So simply getting the J0V update would make the engines RPM higher and louder which it does and is and also cause a possible head gasket issue sooner because of high temps.

By the time I got the update they told me my engine failed commpression anyway.

 

Hi. Any update on this thread?
I am programmed to the dealer 2 days from now on for the update and i don't know if to do it or not....

 

I have a 2015 and do not plan to have an update. 6 years, 75k miles no problems and average 52mpg year round. The gas mileage is the only reason I have the car, if it got 32 I'd rather drive something else.

 

where are you with this? I believe I have something to assist here for you...