Transmission gear hunting

Even my 2015 didn't like me for the first or 4 or 5000 miles. It eventually smoothened out.

 

If transmission or engine control parameters were reset on battery undervoltage or disconnection, I'd be very surprised. Those are the things that evidently get spooled up over a thousand or so miles. More than likely, those parameters are stored in some form of non-volatile memory that survives a battery dying. To reset, I would expect a special series of steps normally done only at the dealership with an OEM software maintenance tool.

On the flip-side, I would expect engine idle or timing parameters, or maybe air/fuel trim based on O2 sensor feedback might get reset on battery cycle because they are learned faster.

But I have no idea to be perfectly honest. Hence the question.

 

Either that, or the truck trained the human up.

 

This is exactly what I hear. I’m planning on going KD Max within a few weeks!

 

Getting a tune would definitely help. I highly recommend OTT. Switched to OTT from KDMax and its a night and day difference.

 

You can reset the DTC, Learned Value, and AT values using techstream. Instructions in post #1 here:

https://www.tacomaworld.com/threads/ecu-tsb-update.562550/

Everyone is so quick to jump on aftermarket tunes.

Id just make sure you have the latest TSB for AT programming applied first. It might even be free from your dealer first before spending money on a tune. You could also buy a Tactrix cable and apply your own TSBs, as well as using techstream to perform maintenance, troubleshoot issues, and apply some minor custom configurations to your truck.

 

Is there a way to check if you have the latest TSB without going to the dealer?

 

Assuming your 2020 is an automatic, the latest is TSB 0045-21 and the latest ECU ID is 04B82. If you have an inexpensive OBDII scanner you can easily read your ECU ID. If it's 04B80 or 04B81 you can apply the O4B82 update. Just FYI, this TSB is for crawl control so asking the dealer to apply it if you don't have crawl control or they can't duplicate the issue may lead to them saying no. A lot of times Toyota sneaks other fixes in there in addition to the problem in the TSB, so having the latest may still improve your issue.

 

Makes sense. Since whenever a smog is done and the parameters dont show up after disconnecting the battery you would have to run the vehicle more time in order for the ecm to learn new parameters. Thought that would be the same with the transmission.

 

I have a 2019 SR5. I'm going to scan the ECU for the ID once i have a chance. Thanks for the info

 

This is the OBDII scanner I have, and it reads the ECU ID reliably:

$17 MOTOPOWER MP69033 Car OBD2 Scanner Code Reader Engine Fault Scanner CAN Diagnostic Scan Tool for All OBD II Protocol Cars Since 1996, Yellow

https://www.amazon.com/gp/product/B07Z3HB7DR?ie=UTF8

For your 2019 SR5 the latest ECU ID is 04B33 assuming you have automatic. You could currently be running 04B30, 31, or 32 depending on when your truck was built.

 

It wouldn't make any difference if the ecm has a memory chip which idk. If so you'd probably have to start by addressing/burning in new parameters much like having a tune done.

 

This is correct, would not make a difference. You actually have to use TechStream or VFTuner (or similar tuning software) to do a Reset Learned Values. Your truck will run like crap for a while after you do that.

 

OTT tune on my ‘21 TRDOR seemed to be only a temporary fix as over time it felt like it reverted back to old shitty gear hunting. Recently put 255/75/17’s on and just like that this thing drives perfect, I think I hit the sweet spot for tire size/gearing. The tune is still there so maybe it all finally came together, who knows… my overall drive ability has improved 95%! Even my wife noticed how much better it drives.

 

Thanks - I just ordered the newer version of that one. Pretty inexpensive.

 

Yea you really can't go wrong for that kind of money, especially given everything it reads.

 

It's 1/2 a bar tab... lol

 

Buys new truck, then has to pay to get it to run right.......and everyone thinks it's ok........shame on Toyota, SHAME on Toyota. Used to be the pinnacle of drivability and reliability, now just another import vehicle.

 

It’s 100% NOT ok! At least not to me…
But I found a solution, yeah it cost me money but it’s working now. The reality is I don’t know what else I’d buy if I got rid of this truck.

 

^^This. No it's not ok, but these issues have been well documented for several model years and shouldn't come as a surprise to anyone. Even if you didn't know beforehand, it would be very evident when you took a test drive before buying.