Hymotion inteferes with Techstream communication??

Simple OBD scanners like the ScanGuage work fine with the Hymotion. No idea why the more sophisticated Toyota tool is defeated by it. You've tried turning the pack completely off via the dash switch and it still interferes?

You might look at the thread here about the auxiliary battery. I had an experience that sounds similar to your customer's experience: turned the car on and it lit up like a pinball machine. Got the red triangle.

The root cause was that the Hymotion pack places a drain on the auxiliary battery as it charges. With the cold weather and all, my auxiliary battery was pretty well discharged when I tried to start the car. And, it has also been reported that just having the Hymotion pack on at startup, with low battery, can cause additional complications.

So if the auxiliary battery was still in good shape, just fairly well discharged, it might have recovered and/or warmed up enough to give you a good start on the next try.

What I'm saying is that you've got several folks here that have gotten a transient failure-to-start because the Hymotion pack recharge drains the auxiliary battery too low. Wouldn't surprise me if one out of your 50 had the same issue. I've installed an automatic-shutoff trickle charger to run when the Hymotion pack is charging, and that solved my problem.

 

I had all kinds of warning lights once. After I closed the drivers door it was all better.

 

Whenever you are working on a Prius with a Hymotion battery, there is something our techs do to disconnect the Hymotion battery before they do anything to work on the vehicle. I forget what they call it. A "dongle" or something like that.

Our techs do this every time before they do anything. Even before upgrading the springs and shocks, they will disconnect the Hymotion battery so that it is safe to work on the car.

 

The owner of the Hymotion conversion should take it back to where it was converted. This sounds like a 12 volt battery issue. During startup if the voltage drops too low, this creates a communication issue.

It typically only happens on older 12 volt batteries. But I think really cold weather could also have an impact on the voltage levels.

I always keep my headlights, radio and all accessories off for starting the Hymotion Prius. If I recall, the recent software update from Hymotion resolves this issue. But I have not gotten this update. I don't really get this error.

 

Hymotion has a fix for the 12 volt problem. They are sending me voltage regulator circuit that goes between the 12 v and the Hymotion harness. This will allow the Hymotion to start properly in cold weather when the voltage drops below 11.5 volts. Without the regulator the red triagle can be displayed although the Prius would start normally below 11.5 volts. I'm waiting on the kit and I will update after I have installed. I noticed a problem on cold days. I did not always shut off the headlights and I added heated seats. Between the two I was able to cause the voltage drop and red triangle stopping the vehicle. After charging the battery, I was able to shut the car off and restart normally.

---Kent

 

DH is thinking that because the hymotion conversion links into the vehicle's electronics, that the extra wiring could somehow be interfering with the techstream communication. -have you tried the vetronix scantool?
-anyone else out there with a hymotion conversion willing to go get theirs hooked up to a techstream to see if it's the hymotion or this one car?
-otherwise, see if there's a wiring harness plug you can disconnect to re-establish the stock electronics.

scangauge is an obd reader, not a two-way communication device. there is a big difference in the way they work.

 

Even when Toyota has their own Plug-In Prius, you will likely still see these aftermarket batteries added.

If Toyota is offering a system that does 15-20 miles in EV, then guys like me would want 40 to 50 miles of EV and do an aftermarket upgrade.

This is just a new version of suped up cars.