Toyota vellfire/alphard new RH66

**deforce2006** · 8th December, 2017, 08:12 AM

Hi all, I just wanna ask if anyone knows how to write this type of chip properly, rh66 for toyota vellfire/alphard 2015+. I have done alot of these chips and still experience odometer freeze sometimes. I read and write it the same way as old vellfire/alphard 93C66 but i never had any problems with the old models before. Any idea what might be the problem? Are there difference between 93C66 and RH66?

**conemotors** · 13th December, 2017, 12:30 PM

check your soldering frist!

**deforce2006** · 18th December, 2017, 07:54 AM

Hi thanks for your suggestion. Tho I'm quite confident the problem doesn't comes from soldering. Any other ideas?

**conemotors** · 19th December, 2017, 04:26 PM

you need how many km?
i made one for you.

**conemotors** · 19th December, 2017, 04:37 PM

some times you do bad soldering when you frist read this small chip and you don’t know.
you can read the right old odo and change the km, but the new odo is freeze.
so you must do 100% good soldering in the frist reading time and solder it back on dash

**Quiet** · 19th December, 2017, 06:29 PM

Originally Posted by deforce2006

Hi all, I just wanna ask if anyone knows how to write this type of chip properly, rh66 for toyota vellfire/alphard 2015+. I have done alot of these chips and still experience odometer freeze sometimes. I read and write it the same way as old vellfire/alphard 93C66 but i never had any problems with the old models before. Any idea what might be the problem? Are there difference between 93C66 and RH66?

how do you fix it when odometer freeze?

**deforce2006** · 19th December, 2017, 09:22 PM

Originally Posted by conemotors

some times you do bad soldering when you frist read this small chip and you don’t know.
you can read the right old odo and change the km, but the new odo is freeze.
so you must do 100% good soldering in the frist reading time and solder it back on dash

Yes I understand but I always check the eeprom before I write since I would need to edit and synchronize to prevent it from freezing like the old models. I notice everytime the odo freeze, the synchronization would run off. Redo the same method would result me the same freezing issue.

**deforce2006** · 19th December, 2017, 09:33 PM

Originally Posted by Quiet

how do you fix it when odometer freeze?

Read again and I'll always see the synchronization will run off. The easy solution is change to other mileage, difference by thousands and synchronize the 17 mileage bytes with the 0000/FFFF in the following.

If I insist on the same mileage with the freezing problem, usually I just keep editing the synchronization in a different way till it works. Funny thing is the method to solve this particular car might not work the same for other, despite being the same speedometer and same model.

I wish I could post the dumps here to have a better look with you guys but my comp keeps reading those dump files as virus and preventing me to transfer.

**Quiet** · 20th December, 2017, 07:33 PM

Originally Posted by deforce2006

Read again and I'll always see the synchronization will run off. The easy solution is change to other mileage, difference by thousands and synchronize the 17 mileage bytes with the 0000/FFFF in the following.

If I insist on the same mileage with the freezing problem, usually I just keep editing the synchronization in a different way till it works. Funny thing is the method to solve this particular car might not work the same for other, despite being the same speedometer and same model.

I wish I could post the dumps here to have a better look with you guys but my comp keeps reading those dump files as virus and preventing me to transfer.

17 mileage bytes it the blue highlighted in the picture?

17 mileage bytes.jpg

then how many FFFF do you put before 0000 to make it work again?

**drpeter** · 21st December, 2017, 07:53 AM

Originally Posted by deforce2006

Yes I understand but I always check the eeprom before I write since I would need to edit and synchronize to prevent it from freezing like the old models. I notice everytime the odo freeze, the synchronization would run off. Redo the same method would result me the same freezing issue.

The problem is you dont know the exact algorithm like most tools, read the chip 16bit post the dump(s) and i will help you.

**deforce2006** · 21st December, 2017, 12:58 PM

Originally Posted by Quiet

17 mileage bytes it the blue highlighted in the picture?

17 mileage bytes.jpg

then how many FFFF do you put before 0000 to make it work again?

No, i meant the top 17 ones. 7702 to 7602.

Usually when I see algo like this, i wont edit anything. Am i doing it right?

**deforce2006** · 21st December, 2017, 01:04 PM

Originally Posted by drpeter

The problem is you dont know the exact algorithm like most tools, read the chip 16bit post the dump(s) and i will help you.

Thanks! But i would prefer if you can teach me how to edit these dumps properly. I'll post a few clean dumps I saved previously and maybe you can show me how you edit it? Really appreciate it.

**aisling2017** · 23rd December, 2017, 11:20 PM

Can a RH 86 eeprom be replaced with a regular 93c86 eeprom

**RayL88** · 17th November, 2018, 08:53 AM

Originally Posted by deforce2006

Thanks! But i would prefer if you can teach me how to edit these dumps properly. I'll post a few clean dumps I saved previously and maybe you can show me how you edit it? Really appreciate it.

Have u discover how to not freeze the odometer for Alphard/Vellfire 2015? I adjusted it and the trip A/B is working but i heard not all car work.. Some will freeze too..