Hymotion inteferes with Techstream communication??

[Bear68]

OK... I have now seen my first Hymotion conversion enter the shop.... Bear with me folks cause I am something of a Purist! If it didn't come from Toyota it don't go on my Toyota.

The car in question is owned by the local power company, (they recently bought fifty Prius from us) The driver stated he placed the car in Ready mode and suddenly "all the warning lights came on". When the car was towed to us, I got in and it went into Ready mode with no warning lights at all. I drove it a couple of miles and then attempted to connect the TechStream scan tool to check for codes. None of our three TechStreams would communicate with the car at all. They simply froze up during the uplink process. I spoke to someone from Hymotion who told me about the bypass connector located near the Hymotion battery, but even jumping it out did not help. We are now waiting for more technical data from Hymotion.

Anybody hear of anything similar??

[chogan2]

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.

[patsparks]

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

[PeakOilGarage]

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.

[Bear68]

Thanks for the input, we are still waiting for more technical info from the Hymotion people. I think the aux batt issue may have been close to home, since a laod test showed it to be in need of charging. (Most aux batteries will show as needing charging) This car is the only one that has been converted so far....

After speaking with one of the Hymotion reps, I found out about the bypass plug, which is supposed to completely disconnect the Hymotion battery. Even that procedure did not allow communication with the car. Unfortunately, the rep only knew how to tell me where the plug was and little else about the system.

Simple OBD scanners can do the little kobs of pulling codes, but cannot give full access to all the computer systems and data lists.

I guess my main concern is that I have no training or information on how this system is integrated, and how to properly and safely (for myself and the car) inspect and diagnose it.

[PeakOilGarage]

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.

[ibcs]

Originally Posted by PeakOilGarage

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

[galaxee]

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.

[Bear68]

Originally Posted by galaxee

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.

Unfortunately, our old Vetronix scan tools have gone the way of most shop equipment: completely trashed. (Pardon my lack of respect for some of my coworkers, some of them are animals)
Hymotion does have a bypass plug located on the driver's side of the Hymotion HV battery. It consists of a white connector in the wiring harness which is meant to be unplaugged and a jumper plug, hanging on the harness with a zip tie, is then put in place on the appropriate connector end. This is supposed to disconnect the Hymotion system completely from the car. Utilizing this plug did not help in this case, however.

At this point, the car has been returned to the customer with these comments:
It's driving normally right now, even though we cannot communicate with it.
We highly recommend you contact your Hymotion representative and have them arrange for a thorough inspection.
We will stand behind the factory Toyota portion of the car as much as possible, but any issues arising from this system will need to be between you and Hymotion, since they have stated that they will send techs to handle any warranty issues themselves.

I still hold hope that they may yet send me some technical information on this system so I can become better educated on it. I think I may yet see quite a few of these coming around, even though Toyota has stated they will have a plug in version of the Prius within the next 2-3 years.

Thanks for the input from all of you though!!

[PeakOilGarage]

Originally Posted by Bear68

I still hold hope that they may yet send me some technical information on this system so I can become better educated on it. I think I may yet see quite a few of these coming around, even though Toyota has stated they will have a plug in version of the Prius within the next 2-3 years.

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.