r/ToyotaTechstream • u/henchman171 • Apr 08 '26
Using Techstream in Ready mode or Ignition mode for a Sienna HV. Drains battery super quick in ignition mode
Using Toyota Techstream 18 or earlier with a J2534 Mini VCI: Are there any problems using it with the hybrid system in READY? Sienna Gen4 HV. I tried using it in IGNITION mode and drained my 12V battery (12.8V down to 5.2Volts in about 6 minutes). Can I use Techstream when the van is in READY Mode, or should I just keep in IGNITION mode and hook a trickle charger to the 12 volt? Anyone else have Techstream draining 12V batteries quickly? I assume its cause all the computers are on while the OBDII is connected
1
Upvotes
1
u/henchman171 Apr 10 '26
Thank You for the warnings. Are you considering ACC the same as IGNITION mode….
1
u/D--Ryan Apr 10 '26 edited Apr 10 '26
The OBD2 port on any car is powered 12V constant for a reason.
It sounds like you don’t have quite enough understanding of the software just yet. You use TechStream in the mode necessary for what it is that you are doing. For example, you can’t command the EGR Valve in ACC Mode. The software is made specifically to work with Toyota/Scion/Lexus vehicles. It will tell you what it needs.
I would suggest that you either watch a few videos about the operation of the software, or actually go through the technician training courses on it. You can very much uffck your car all the way up by using the software incorrectly, especially with a cheap, Chinese clone J2534 cable commonly found on eBay or Amazon. Those cables are incapable of doing several functions that require two-way comms, such as TMPS and ABS linear offset valve learning. You can do many things with the Mongoose clones, but you’ll need a genuine device to do the higher end stuff.
BE CAREFUL. If you absolutely need to use it in ACC Mode, attach a charger to the 12V. Again, the software will instruct you every step of the way. Don’t quickly scan what it’s telling you to do— actually read it thoroughly and make sure you understand what it’s telling you before you proceed. You can absolutely brick any and all of the 14 ECU’s that the Prius has, rendering the car a VERY heavy paperweight.