How to make Power Mode the default driving mode.

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This is still the early stages of my research. More info coming soon. But first, I gotta finish doing my taxes... I mean start doing my taxes.

 

Default PWR Mode mod will available in PriusChat Shop soon.

Modification Outline
1 - Understanding PWR mode
PWR mode can only be activated after the Prius's computers has booted up. This takes approximately 1 second. Holding down the PWR button while powering up the Prius will not enter PWR mode therefore it is necessary to build a delay pulse circuit. A delay pulse circuit instead of a delay latch circuit is required because a delay pulse circuit will allows you to deactivate the PWR mode later while a delay latch circuit will not.
2- locate the IGN-ON wire
It is not necessary to locate the Ready wire. PWR mode can be activated in the IGN-ON stage. When PWR mode is activated in the IGN-ON stage, it is retained in READY stage.
ACC-ON wire such as cigarette lighter wire can also be used as long as you don't turn on ACC-ON before powering up the Prius. ACC-ON must be cycled off before powering up the Prius if you choose to use the ACC-ON wire.
3 - locate the PWR mode wire
Instead of telling you which wire it is, I'm showing how to locate the wires from scratch. This method should also work with the Prius v.

Remove the shifter bezel

Disassemble the mode selector assembly by prying the lock tabs






Disassemble the mode selector circuit by prying the tabs and unscrewing 2 screws




The circuit should look something like this


Circuit testing

use a multimeter and set to resistance reading. Use the probes to test the SW3's terminals. This will tell you if the bush button has no resistors built in and it's a straight connection when the button is pushed.

Finding solderable locations if you don't want to cut any wires or make any connections to the harness.

Using the multimeter again and use the continuity test. Probe the left terminal of the push button switch then probe each of the solderable points on the back of the circuit. Once you've found the correct solderable point, the multimeter should beep to indicate that solderable point and the left terminal are the same circuit. Do the same for the right terminal of the push button.
For my Prius, the left terminal is T10 and the right terminal is T12.

If you don't mind T-Tapping wires, you can do the same test as above but instead of the solderable points, probe the pins of the harness plug.

For my Prius, the left terminal of the switch is pin #7 and the right terminal of the switch is pin# 5. The wire colors on the harness is Green for Pin#7 and white/black stripe for Pin#5.

Make channels for the wires on the PCB cover

Once you've soldered the circuit board, you'll have to cut the circuit board cover for the wires to route out of the PCB assembly. You'll also have to drill a small hole for the wires. If you use wires from a CAT5 cable, you should be able to get away with not drilling the hole for the wires however, you'll still have to cut the circuit board cover for the wires to route out of the PCB assembly.

Reassemble the PCB assembly.


Strip the wires and make your connection


I use molex connectors for quick disconnect.

Finished wiring


Once you have everything assembled, use the multimeter and do a continuity test between the 2 wires you just made. The multimeter should beep when the PWR mode button is pushed. If not, go back and recheck your work.

Once you've verified all the connections are good, plug in the mode selector and the park harness and power up your Prius. Shorting the 2 wires you've just made should put the Prius into PWR mode. If not, go back and recheck your work.

4 - building the circuit
You'll need 2 DEI 528T and a standard 12volt SPDT relay.


The wiring is straight forward. Follow the diagram and it should work. Everything is color coded to the 528T and the SPDT relay with harness. If there's no harness on the SPDT relay then follow the pin layout.
If you can't follow the pin layout, you can follow the numbers printed on the relay.
30 Yellow - Common
87a Orange - Normally Closed
87 Brown - Normally Open
85 Black - Ground
86 Red - Power
If you connect the red wire to ACC-ON such as cigarette lighter, you can bypass the default PWR mode by turning on ACC-ON first then goto READY mode. Doing this sequence the second 528T will activate before the Prius will accept the PWR signal therefore will not enter PWR mode.
If you connect the red wire to IGN-ON or READY mode, the only way to turn off the default PWR mode is by adding an ON-OFF switch.
The 528T is factory timed to around 30 seconds so you'll have to adjust it accordingly.
FYI, The 528T will accept a +12v as trigger on the black/white stripe wire by cutting the blue loop. However, The internal relay will only activate after the +12V activation signal has been removed. This will not work with what we're trying to do. This means that the delay timer relay will only start after the Prius has powered up and powered off. This is why it requires a SPDT relay to convert the +12V switched to -12V and use it to trigger the timer relays.
The 528T in the middle of the diagram is the main delay relay to which the PWR mode will activate. Set this pulse timer to 1.5 seconds if you want PWR mode to activate as soon as you power up your Prius. Set it to 90 seconds if you want PWR to activate after the Prius has warmed up a little.
The 528T at the bottom simulates the PWR button being pushed. Set this pulse timer to about a second or less. The Brown and Yellow wires are reverseable so it doesn't matter which wire you hook it up to.
The PWR mode can be turned off and on during vehicle operation. The circuit is only active the first few seconds of powering up the Prius. After that, you have total control.
If you have successfully done this mod, or built a circuit other than what I have, please share it with us. I would really love to hear how your mod turned out.

 

plugins can start in ev mode. i dont expect people to be interested in this mod like my other one.

 

I have seriously considered posting the 555 timer circuits. However, less than 1% of people on this forum can build 555 timer circuits. I want to show a simple way that anyone can do.

 

yes I've taken apart the mode selector switch. there's a spot where you can solder on the circuit board if you don't want to cut any wires. the switch is a SPST momentary push button switch. it's a straight short when the button is pushed.

 

I built a circuit out of a standard automotive SPDT relay and 2 528T pulse timer relays.

The SPDT relay converts the ACC-ON's positive to negative that will be used to trigger the first 528T. The first 528T, timed at around 2 seconds, delays the second 528T's trigger til the Prius is in READY mode. The second 528T activates the PWR mode after the first 528T has timed out.
The circuit was bench tested to be functional. I installed it into my Prius and tested it out. It works perfectly.

 

ny_rob did you get a chance to build this circuit yet?