Speed Sensor Defeat Update

[NorthStar]

There is a wire on schematics for the parking brake going into the Multi-Display - slot #16(connector M13). I've read on a Lexus site that mods for some of those cars require a similar defeat for the parking brake. Might that be the case for the Bluetooth? You'd have to pull apart the dash to get at this red wire.

Mark

[brosnan]

Here's how to defeat the speed sensor's lockout of certain Bluetooth phone features while moving:

- Remove dash panels to gain access to the MultiDisplay.
- Cut the violet wire going to pin 25 of connector M13 on the top of the Multidisplay. This wire is one slot away from the end (pin 26) and is all alone in a group of 6 or 7 unused slots.

- Route 2 wires to a switch you or your passenger can reach. Right now I'm using a magnetic alarm switch behind the bottom center plastic panel under the radio (+ a magnet on the cabin side of the plastic to control it).
- Connect the new wires to each side of the cut wire.
- Solder and tape up the splices.
- Re-assemble dash.

With the switch closed, the speed sensor output is delivered to the MultiDisplay as normal. You will not be able to access the Phone Book nor dial numbers on the touchscreen while driving.

With the switch open, the MultiDisplay does not receive speed sensor pulses and all the phone features are available at all times. The only side effect I've seen so far is that in the info display animation, the tires don't spin. The distance display seems to advance and the mileage values and power flow arrows seem normal.

Finally I can finish checking voicemail when the light turns green without fumbling for the phone!

Do this at your own risk! Drive safely!

[efusco]

Way to go Brosnan!!!
:multi: :clap: :clap: :clap: :clap: :multi:
I'd identified that wire on a w:clap: iring diagram as a good possible choice to divide to defeat the Bluetooth, but didn't have the knowledge/guts to try to find it and cut it.

If you don't mind, could you either e-mail me or post here how to get access the the MFD, if you can do that I'll do another full photo write up of the proceedure.

I may just divide the wire if the only side effect is the wheels not turning on the Energy screen.

Again, great work and thank you thank you thank you!!!

[Danny]

Brosnan, you might as well be Pierce Brosnan on this board, because you're the man! Good job!

Throw this baby into the Knowledge Base as soon as we get a solid writeup on it, Evan or Brosnan.

[efusco]

Brosnan,
A quick followup, did you try to trace that wire anywhere else that it might be easier to access or to splice a switch into? The back of the MDF doesn't seem to be the ideal place.

In my case, ideally, I'd like to add another switch that matches the one for the NAV and put it immediately next to it, or to actually splice this into the same switch for the NAV defeat so accessing any of those features on the MFD would be one easy switch to trip.

Man, I don't know when I have time to do this, but it'll happen in the next week for sure. Please, someone let me know the best way to pull off the dash pieces to access that area.

[brosnan]

The PriusXM installation video ($29 at https://secure.priusxm.com/order.html) is very useful for anyone needing to open up the dashboard to get to the MultiDisplay or radio. When I get some time I'll write up a good description here.

The really short no-photo version is that you:
-snap out the far left A/C panel (by pulling forward)
-open the glove compartment top and bottom
-snap out the A/C panel just to the right of the radio
-snap out the center floor cover under the radio
-remove the screw next to the Keyless Entry Defeat switch
-snap out the panel containing that screw
-unscrew the screw on the left which now uncovered
-snap out the panel containing the start button
-snap out the A/C panel just to the left of the radio
-with a 10mm ratchet wrench, remove the 2 bolts holding the MultiDisplay
-snap the MultiDisplay forward - but don't let it jump too far


The wire in question disappears into a cable bundle heading
deep into the dash. Although it may be accessible elsewhere,
that was not immediately obvious.

[efusco]

Thanks again Brosnan. I think I can do that with the step-by-step instructions you listed. I'll probably hunt around a little for that bundle.

I think Coastal Dave's method of installing the XM system doesn't involve removing the entire dash, he's figured out that you can just reach behind there to do it, but it seems most prudent to visually ID the place the plug goes and the exact wire in this case.

[brosnan]

Some additional notes on this mod:

1) Besides lack of animated rotating tires, you also lose the history
aspect of the MPG bar graph. In other words, the 5 minute rolling
MPG graph has no green bars on it after cutting the speed signal to
the MultiDisplay. Interesting, the regeneration car icons still show
up and slide to the left over time. The bars will be drawn if
the speed signal is connected at certain times. You don't need
a continuous connection. I'll try to learn more about that. Perhaps
some kind of timer circuit can be used to get both the MPG bargraph
history and full phone features.

2) If you do this mod, then find the car won't start, don't panic.
You've probably just bumped the keyless entry defeat button
under the steering wheel. Press that button again to bring the
car to life.

3) The maintenance screen and calendar (and map features) are
not affected by this mod - only the phone features are restored.

Interesting comment about not opening the dashboard. Perhaps a small
hand could get to the M13 connector by simply snapping off the
A/C cover just to the right of the radio. There is a bit of slack
in the cable.

[8AA]

efusco,

Before you install a second switch you might want to check to see if the style of switch you already have comes in a DPDT variety (this came up in the January posts). DPDT (double pole double throw) looks the same, but is actually two separate switches connected to a single button or lever. There is also a DPST (double pole single throw) which is the same except both switches are either open or closed at the same time. There isn't a significant price difference between them, and a DPDT switch can be wired so that one switch is open, while the other one is closed.

[efusco]

efusco,

Before you install a second switch you might want to check to see if the style of switch you already have comes in a DPDT variety (this came up in the January posts). DPDT (double pole double throw) looks the same, but is actually two separate switches connected to a single button or lever. There is also a DPST (double pole single throw) which is the same except both switches are either open or closed at the same time. There isn't a significant price difference between them, and a DPDT switch can be wired so that one switch is open, while the other one is closed.

Thanks VP,
Good stuff to know. Despite the mods and write-ups I've done I don't have much solid knowledge of this stuff. I thind the DPST would be fine since I can only look at one screen at at time and there's no down side to defeating both speed sensors at once, that I can think of.