Hymotion and Coastal Tech EV switch

I have a Hymotion and put my own EV button in using efusco's guide. The main difference between a straight out button like mine and the Coastal Tech version is that the Coastal version need to held for 2 seconds before it will signal EV mode to the hybrid computer.

Both the Hymotion and Coastal mod need to use the same pin on the hybrid computer, so you have two options; replace the Hymotion wire, or splice the Hymotion wire.

Option 1:
The problem with replacing the wire is that the Hymotion will stop automatically setting EV mode when you slow down or after the engine warm-up finishes.

Option 2:
The Hymotion likes being in control, and you will see the EV mode flip on/off constantly if you ever trigger it manually. The engine may or may not shut off, and it may end up running with EV mode "on". Fear not, there is a workaround!

I went for option 2 and I've found that if I hold the EV mode button for 3-5 seconds, the two system stop fighting and it sets EV mode consistently. However, if you're going the Coastal Tech way, I assume it's because you'd prefer the plug-n-play simplicity, so you'll have to weight your decision against giving up the automatic EV mode from the Hymotion kit.

 

The wiring portion was pretty straightforward; I didn't solder anything, I used splicing clips. These are some pix of the clips I used...
Installed: http://zeroreality.net/pix/phever/phever_090.jpg
Parts: http://zeroreality.net/pix/phever/phever_091.jpg
Usage: http://zeroreality.net/pix/phever/phever_094.jpg

The blue one clips onto the Hymotion wire (orange), cutting the wire's sheath on two sides and touching the metal. Once it's on, you use the red one on top so you can connect and disconnect as necessary. Also in the pix is the U-connector which I connected to ground which was just some bolt holding the air filter on.
The actual button I used looks like this: http://zeroreality.net/pix/phever/phever_079.jpg

The Hymotion works pretty much as you described; sending a false 80% charge indicator to the hybrid control computer which then biases the car to use more battery juice instead of dino juice. It also sets EV mode when travelling under 52Km/h (not sure of the mph equiv).

Avoiding the warm-up cycle is a pain with the Hymotion kit and it will actively prevent you from setting EV mode manually... but again... there is a way; reverse. Putting the car into reverse will temporarily stop the kit from sending the spoof packets and it won't set (or unset) EV mode. So to do it right; turn the car on, put it in reverse quickly, and hit the EV mode quickly. You need to complete those steps usually before (or just after) the centre touch screen comes up at the menu. After you shift to drive the Prius computer and the Hymotion begin "fighting", but if you stay under the 52Km/h (or whatever the mph equiv is) you won't need to worry about it. However, if you do hit 52Km/h then you will get stuck doing the warm-up cycle.

 

Personally I would just cut the Hymotion wire and leave it out of the loop. Just when you cut it leave enough wire coming from the connector side so that you can tap on to it with your EV button.

And I would go with a real EV button as in either the factory style button of if your wanting something cheap a momentary switch button. That way you can have EV mode instantly instead of 2-3 seconds from when you press it.

 

If you just want a button any momentary button will do and its easy to install. Might be even easier than the coastal even if you have to do some soldering and crimping for the wires and wire connectors. Worst case a lighter and some solder will do and a pair of pliers for crimping the connections. The hard part ( inserting the pin into the wire harness ) is all ready done by Hymotion but of course they would use the correct pin instead of an over sized sourced one from the steering column.

Buying an OEM EV button for $75 will include everything except some wire taps and wire to fish to the other side of the car.

Where are you located? There might be another Prius owner near by that could help with the install.

 

TheForce is correct; just cutting the Hymotion wire off and using your own button is easier. The reason I suggested splicing the wire is because you wouldn't lose the automated EV mode set by the Hymotion kit.

I've been thinking about just cutting the wire so I have finer control over EV mode. I have also considered a cutoff switch which will isolate the Hymotion so it can't set EV mode but I can. And just Monday I started salivating at pEEf's thread where I might be able to program an external module for super-EV-mode (if he shares his knowledge of the engine/hybrid CAN bus).

If you're looking for ease of use; the Hymotion does it for you, why change it?

 

Can any of you folks help me? i have the Coastal EV module (switched by pulling the cruise stalk toward you for 3 secs)

i also have a Hymotion pack.
The Coastal module was spliced into the white “EV-button” wire that comes from the Hymotion harness, to Pin 27 of the bottom/ H16 connector on the HV ECU.

A couple questions:
For quite a long time now I have had random beeping at 50 to 60 miles an hour saying "Cannot enter EV mode"… Apparently something is requesting EV mode. I don’t touch the stock… I don’t go over any bumps… I’ve tried all sorts of banging and slapping to see if it’s a loose connection and nothing seems to engage it reliably and it’s very intermittent… Today when I took it apart I did notice that the orange wire going into the connector on the HV ECU was slightly out and - I mean very slightly -so I pushed it in harder and I’m hoping to see if that stops the intermittent issue.
>I wonder if anybody has ever had that happen: EV being requested during high speed without being touched.
I don’t know if it’s a bad module or a short in the wire or interplay.
Regardless, the next step in process of elimination, Is clip either the Hymotion wire or the coastal wires and eliminate them from the equation, to see if they are causing a problem or cross talking.

But the other question I that I have: there is a white mystery wire that has been clipped coming out of the bottom connector on the -engine- ECU.
Does anyone know what this wire is, or what that pins function is?

watch video to see:
2007 Prius ECU & EV Mode connections - YouTube

 

When you compare the location of the white wire from the engine control module and the mode EV wire from the hybrid system control module, you will notice that the connector is similar. Pin number 27.
Perhaps at first they tried to connect to the engine control unit by mistake.

 

Thanks Max! Definitely a possibility… I wonder if there is a schematic diagram that shows a pin out of all these ECU modules and all of their connectors maybe somebody knows where to link it for me