Caution: The transmission lock mechanism is abnormal

When does this screen display?
Over the last few weeks I have had something pop up on the MFD and beep, but it changes back so quickly that only the most recent time was I able to see the words "Caution" and "transmission" before it vanished.
It has happened at highway speed an hour into the drive, at <20mph 1 minute after I started the car in the morning, and while demonstrating EV mode to a friend. There seems to be no comonality that I have found.
Or do you think that I am getting a different caution statement?
thanks
Jeff

 

It happened again on the way home from work last night! This time while sitting at a stop light facing uphill. Other instances noted in previous post.
It comes and goes so quickly that when I notice the change and turn to look, the screen is changing back and I only see it for a fraction of a second. Is this something I should be seeing the dealer about immediately? I only have 2300 miles on it so far.
Is there a list anywhere of all the possible warning messages that could be displayed?

 

Mmm, I don't know about immediately, but unless you have access to Toyota's proprietary scan machine I'd say that a visit to a dealer for diagnosis is in your future.

 

You'll probably need to wait until you have a warning light come on and stay on. Otherwise it is likely that your dealer tech will diagnose no-trouble-found and charge you for one hour of labor time.

 

What were the two DTC?

Given the existence of the DTC, did the dealer tech recommend taking any action; or does the tech want you to wait until the problem gets worse?

 

To rule out a bad ground, I would back off then snug up the bolt that holds the ground wire connection to the unitbody, at the 12 vdc battery

What exact DTC were reported?

 

DTC C2300 "Act System Malfunction" - possible trouble areas include the shift control actuator, transaxle parking lock control relay, transmission control ECU, or wiring harness.

DTC C2318 "Low Voltage Error" - this is logged when battery voltage at the transmission control ECU is measured to be 9.3V or less. Possible trouble areas include the HEV fuse, IGCT relay, wire harness, or 12V battery.

I can see that this is a serious problem esp. when it happens to your wife and child in hot weather. It sounds like the dealer is not able/willing to take any action since the problem is intermittent and probably cannot be duplicated at the dealer's site.

If this were my vehicle, I'd be inclined to replace the following parts in this order, assuming that the 12V battery is fully charged and in like-new condition when the problem occurs: IGCT relay, then P CON relay, then the shift actuator.

 

I think that none of the items would be covered. If you buy the relays and install them yourself you might pay $75 each at your dealer's parts dept; less if you buy from one of the Toyota dealers that offer 25% discount pricing over the web.

If you are mechanically inclined and have metric sockets you can probably replace the shift control actuator yourself; this would require getting under the car and finding the assembly mounted to the transaxle case.

If you wish to DIY it probably would be a good idea to replace the HEV fuse first, since that should be the least costly item on the list.

 

It only happens on hot days (yes I live in Vegas). All winter long - no problems. First day of 100*F it does it again.

Any time I read this, heat plus electrical problems, I wonder if the problem is a inverter that is not being cooled, thus giving electrical problems. Do you have good circulation in the inverter cooling system? Maybe the pump is slowing down or other cooling problems . If you have an infrared thermometer, check the inverter case when you have the problem, mine runs under around 120 degrees on really hot days. FYI when my inverter pump was out(and I didn't know it), I was able to drive about 30 minutes with the a/c on before I had the dtc's show up. Opening up the hood, the inverter I could tell was very hot.

 

If the problem usually happens upon first startup, then you can rule out the inverter coolant pump as an issue. That might be a suspect if the car has been driven for a period of time and then develops a symptom. However other DTC would be logged in that case, relating to the inverter overheating, while other ECUs would also report low voltage on the 12V bus.

 

Glad I found this thread!

I've got a 2005 w/over 100K miles on it. Never had a problem until Friday and now this. My car has been at my dealer for the last couple of days and they really don't know what's going on with it. They have seen the problem however so that's a good sign.

I suppose that after 5 years it is time to change the batteries but I have one question for those who have experienced the "transmission lock" problem:

Did replacing the 12v battery resolve your issue with the message and the car not starting?

 

Thanks for the update Highspeed!

My car is still at the dealership. I was out of town over the weekend but my service rep left a voice message on Saturday that my car seemed to be ok even though they couldn't identify nor fix the problem.

They've got volt meters at both ends of the car. The meter at the back is reading a solid 12v but the meter at front is showing strange voltage drops.

I called this morning with the intention of picking up my car when I got back into town and the service rep went out just to make sure that everything was ok. Well, the good (??) news is that the car is acting up again so I hope they can isolate the problem.

I wonder what is going on with this issues and I hope that Toyota is working this as well. Seems that more that a couple of folks have this problem.

I'll keep this thread posted.

 

That implies a loose cable connection, or a damaged battery cable between the two meters. The 12V battery cable runs with the high voltage traction battery cables along the bottom of the car, driver's side.