TSB EG-0127T-1014 (SW update to avoid cylinderhead gasket failure)

I was going to say the number of the document doesn't look like the ones that come out here in the US. I probably can't download it from NHTSA. Maybe @Elektroingenieur knows something about it.

 

This seems to be the document:

 

Thank you for finding the TSB from "Toyota Motor Europe NV/SA" and adding it here.

So, the $1,000 question, did Toyota implement this software update worldwide? My guess is that they did, and any 2015 and newer Prius with the 2ZR-FXE engine would have the updated software from the factory.

I had the ECM in my 2011 Prius updated two years ago for a different reason. My calibration ID before the update was 34728000, and after the update was 34728500. So, I am assuming I have the updated software for the water pump. This makes me feel a little better about the head gasket in my engine. I am hoping to get to 200k miles. I am now at 140k miles.

 

Well, that's interesting. That European TSB looks close to Toyota admitting they goofed, considering their "severe driving conditions" include conditions that are very common in typical consumer use of a car. To quote. in part:

"Some customers may experience and report one or more of the below phenomena:

• Engine coolant consumption
• White smoke from the exhaust caused by coolant consumption
• Rough engine running / misfire caused by coolant consumption

"In some unique severe driving conditions, the engine coolant temperature can rise above a specific value, in certain areas of the engine block. If this specific temperature rise occurs frequently (severe driving), in combination with higher vehicle mileage (vehicle mileage above 200.000km), there is a risk the cylinder head gasket may fail.
Classification of severe driving/usage conditions:

• Long period of engine idle time e.g. taxi use, city parcel delivery, traffic jam, etc
• High percentage of “stop / take-off‟ (go) operation e.g. traffic jam, city / door-to-door driving, etc
• High percentage of high speed / high load operation ..."

I wonder whether the 34728500 update would reduce risk of head gasket failure enough to justify whatever they'd charge--if it's available.

 

Well, it seems like there's a bit of guesswork involved, because unless I've missed it, they've never put out an exactly parallel US or NA TSB that says "here's the firmware version where we fixed the water pump head gasket thing".

I see that the 34728500 version (if you have a 2011) is the version they want you to update to both in T-SB-0103-12 (which is about an intake manifold change) and in T-SB-0027-16 (which is about an EGR valve change). The one TSB says nothing about changing the EGR valve, and the other says nothing about changing the manifold, and yet they both want to get you up to that firmware version for some reason ... which clearly isn't specific to which manifold or EGR valve you have. So there's something else they like about that version. Hmm.

That version is also later than the one released for T-SB-0041-15 to avoid backfires that blow hoses off the manifold and mess up the purge valve, so updating to the later version probably takes care of that issue too.

Be aware that you have to look in the TSB (either T-SB-0103-12 or T-SB-0027-16) to see which version ID is the right one for your car. 34728500 is only the right answer for a 2011. For mine, it would be 34715700. And so on.

In my experience, any time I go to the dealer and ask them to flash an ECU, they simply charge the shop rate, about one hour. I'm not sure it really takes them an hour, but they are supposed to do a bunch of prep work, uncovering the 12 volt battery and putting a DC power supply on it, and pulling some fuses so there won't be any sudden loads during the reflash.

If you have a bunch of stuff in the hatch area you can save them time by clearing it out first, and if you've added electrical accessories they don't know about, pulling your own fuses for those first might help avoid surprises.

 

Im confused.... excuse me for my ignorance here.
Is THIS the reason for head gasket failures, and not EGR circuit cloggage? What am I reading here? What is happening? lol

 

toyota claims it is, and yet they have not addressed north america.

some still believe pistons/rings/egr circuit

 

Ha ha! That's good!

 

Im kind of a big deal

 

I'm inclined to suspect the same code is changed in the later North America firmware updates (the ones mentioned in T-SB-0103-12 and T-SB-0027-16) and Toyota just wasn't as forthcoming about it in those TSBs as in the European one, probably because the European regulatory agency won't brook as much vagueness as NHTSA will.

In any case, I can't think of real compelling reasons not to run the updated ECM firmware in a Gen 3; no telling how many little things they may have fixed, compared to code originally written for 2010 or 2011. The aforementioned purge-valve kablooie glitch, for instance.

And it's not like getting your firmware updated forces you to leave your EGR clogged.

But as long as there is a definite thing that Toyota has come right out and says damages their gaskets, I'm inclined to listen to them about that.

 

Dang it... I was REALLY looking for a reason to avoid tearing into the EGR system too....lol. You ruined my buzz!

 

There should be a 3rd button, and the one Bisco pushed, "Sell this car before it's too late."

 

My enthusiasm about this software is about on par with when someone asks “could pouring such-and-such cleaner in the tank” clear up the EGR?

 

Except that one is from "someone" and one is from the people who wrote the software that makes the car go, and know what they got wrong in it.

 

What do you suppose are the temperature limits they’re trying to hold short of with this TSB?

We routinely see 199F on water, 194F on oil at highway speeds, with a five degree split between the two on the rise and drop.

 

It seems like what they're talking about in insufficient coolant flow velocity leading to excessive differences in temperature between different places in the engine. The temperature readings you see come from the place where the sensor is, and they seem to be concerned about a temperature where you're not seeing.

 

So they demand greater margins to assume away what they can't measure?