Main dash went blank - accelerator dead

Just wanted to post this for the record and to see if anyone has seen this one before (I can't find a mention of it yet) - I'll provide updates as Toyota works through the problem.

I was driving along, at roughly 85 km/hr and then my main dash went "blank". By main dash, I mean the "reflected" area that shows the speed, fuel guage, transmission and engine status. The indicator lights on either side of the dash were still on, and the centre screen was also operational. The accelerator was also inactive (i.e. could push it, but it did nothing), but brakes and steering all seemed fined.

So I put on my 4-way flashers (hazard lights) and pulled over to the side of the road (unfortunately no shoulder on this road) and tried to "reset" the car by powering it off and then back on. I was hoping it was just a simple software glitch requiring a soft reset.

When I powered it back on, the main dash still remained dead - I tried putting the car in drive (D) after waiting a few seconds for startup to occur. The park (P) indicator went off and then the gasoline engine kicked in - I tried depressing the accelerator, but no movement (the parking brake wasn't on). I then turned the car off - gasoline engine went off also (as one would expect).

So I called roadside assistance - while on the phone with them - I tried the to start the car again, just in case time would help. Almost the same result, except this time the car would move, but still no dash. Roadside assistance and I decided it would be a good idea not to try moving it and to wait for a tow truck - just to be safe.

While waiting for the tow-truck, I tried the sequence again a couple of times, and got the same results (one time with no movement of the car, one time with movement, but no main dash for either attempt).

The car is currently with one of the local Toyota Dealers - hopefully they will look at it today and be able to get some data out of the computer system. They didn't want to speculate on what the problem might be over the phone.

As mentioned, I will post updates about what happens.

Car background (for those that want to know):
The car is a 2005 Canadian model with Package B. It has had all its services so far and has less than 24000 km on it (can't check the odometer as dash isn't working). It has previously had one engine light occurance(apparently related to the crank shaft) - Toyota dealer checked it out and cleared it, but didn't find a "real problem". Otherwise, car has generally bahved properly.

 

So to answer people's questions:
- I didn't see any warning lights, red triangles, etc -- nothing that I would expect to see with normal engine issues
- Other indicators, like head-lights, door indicators, etc all were working properly

It was very wierd, that's for sure.


So I've just got off the phone with the dealership, and here's the scoop (not much unfortunately):
- When they started the car this morning (it was dropped of by tow-truck the night before), it was working fine (problems never continue when you want them to)
- They haven't seen it before (not too surprised here)
- There were no engine codes, but there was a "log entry" indicating "gateway error" (explained as a communication problem between ECUs (computers))
- They discussed with Toyota (guessing: Canada head office/service) and went through normal diagnostics -- nothing showed up. Sounded like Toyota hadn't observed the problem before either.
- Dealer really wanted to do some more testing tomorrow as the person I talked to wasn't really comfortable letting it go without knowing more about the problem, but we need our car back, so we are going to pick it up and hope it's a "one off thing".


Hypothesis (mine, not Toyotas):
- communication link between computers got confused
- basic power off and restart did not reset the link
- leaving the car off for an extended period (overnight) causes a "lower-level reset" or "resynchronization" of the computers


At least I can say that it seemed to have failed safely and that there didn't seem to be a risk of serious injury related to the failure.

 

I'd lay odds on it's a computer related problem, probably software, related to an infrequent and unlikely condition that occured, but wasn't anticipated by the designers.

So I've picked up the car - everything seems fine for now.

BTW, the car has ~22 500 km on it (now that I can read the dash...)

 

Hard resets often temporarily fix problems (such as synchronization problems - which this might be).

However, the dealer couldn't (or maybe wouldn't) tell me how to "hard-reset" the Prius.

I get the feeling that it might do a "hard reset" after being turned off for a while. It certainly does a soft reset when powered off, but since there are various things active for a period of at least 10 minutes after "power off", then I would imagine the computers are still running (in some capacity).

I know that powering off for less than 15 minutes did not solve my problem, but powering off overnight did.

 

Thanks for the info on the gateway error. As you say, maybe that's unrelated. The dealer did mention something about key-FOBs in the same sentence, so it sounds like they are aware of the item you are describing.

Anyway, apparently it wasn't a "one-off". The car is back in today - the problem happened again last night. This the car had been running for very little time - my wife had just put gas in and started off. She didn't notice a problem with the accelerator (or any control mechanisms), but the dash went dead again.

Ironically when I talk to the dealer, they don't seem to interested in collecting data from me about what was going on. I would have thought they would be eager for more information - I know I would in their situation.

Maybe I was imagining the accelerator problem when it happened to me. It's possible that when I tried to start it again, it was just not going into drive (D) [with no feedback from the dash - this could be hard to tell].

The dealer is running the remaining tests that Toyota had suggested they run - hopefully we can leave the car longer this time.

This dealer (or dealers that this owner operates) rarely gives loaners to Toyota owners - I've asked before, but as far as I can gather, if you're not a Lexus owner (and thus paying twice the price for services), you don't get a loaner. Maybe I'll ask again if they cannot find anything by the end of the day today - hopefully the nature of the problem will change their mind. Suggesting having the tech drive the car for a few days might be a good idea. [Maybe I ought to see him drive first ]

I'm quite aware of the difficulty of troubleshooting (I'm in the software development business) so I know how hard it can be to fix something you cannot make happen. Which is why it's always disappointing when the problem happens after the service department is closed. Ideally I'd like it to happen, then drive it right there, and go "see, there it is, grab the data now...". We tried to take it to another dealer last night (same owner) who's service department is open later, but they said they wouldn't be able to look at it before they shut.

Again, I'll pass on what happens...

 

So I've talked to the dealer - who've been busy talking with Toyota. They've decided to replace the "combination" computer (I think he said computer). Anyway, they're are replacing the controller for the main dash, which also includes the odometer settings.

Unfortunately, they say the odometer is going to be reset to 0 - which is unfortunate - I got the impression these modules could be ordered from the factory with the odometer reading pre-programmed, but I guess they aren't prepared to wait long enough for that to happen (actually the dealer didn't seem to know about this option).

The part is one day away, so I should have the car back tomorrow evening.

 

Sorry for the delay in following up...

So here's what has happened:
- The combination computer has been removed and replaced (involved removing most of the dash - all back together nicely now)
- The odometer has been reset - there are special letters and forms that get issued, so I don't imagine having too much trouble with resale issues. Dealer insists he's never heard of ordering a compbination computer with the odometer preprogrammed. Maybe we can't order the same parts here in Canada (these types of things are typical or Toyota Canada versus Toyota USA).
- The combination computer had slight "browning" near two of the contacts that connected the wiring harness connector to the circuit board. (I examined it myself.) Not a typical short circuit from my observation, but might have been enough to cause problems. I didn't take in my multi-meter to check out the connections, but it's going back to Toyota for investigation.
- As a result of replacing the combination computer, the "reverse beep" got reset - that setting must be stored in that device. I've since put that back the way we like it - off.
- The dealer is interested in hearing about ongoing status and is showing a reasonable interest in making sure the car is okay.

So far, the car seems to be fine. It would be hard to tell if it has been properly diagnosed. They did work through the stuff with Toyota, so I'm sure they did most of what they were capable of doing. I hardly expect most of the mechanics to be digital computer technicians as well - a complete understanding of the full workings of this car would require a fair amount of expertise, and a lot of (changing) documentation to go with it.

Again, I'll drop a note if anything happens again.

Speaking of irony (as opposed to the poetic justice comment ): I received a general survey by mail about servicing of the vehicle from an "independant survey organisation" the day the car went in for service.

Right now, we're happy to have a working Prius again -- It's still our favourite car!

Oh, one more thing.

Apparently there was another "code" in the log. The dealer told me what it was, but I have since forgotton - sorry. It sounded more related to an issue with the combination computer. The dealer certainly to leave me with the impression that that code was more helpful in the diagnosis of the problem - which led them to the removal and replacement of the combination computer.