check engine, (!), red triangle, VSC light - 2008 Prius stalled downhill

Well, you've been told that the hybrid vehicle ECU needs to be replaced if DTC P0A1D reappears, and I would say that is consistent with the symptoms that you described. Since this is covered under the 8 year / 100K mile hybrid system warranty, what is the basis of your complaint?

 

The HV ecu is covered under federal emissions 8yr/80k miles so you shouldn't be paying for replacement.

 

Had my 07 since new and have never heard the battery fan turn on once but you state plenty of times. It turns on of course from high battery heat. Why would the car incur high battery heat with a fully charged battery rolling downhill slowly? I could see maybe on a hard up hill climb.

Under what circumstances do you see the fan come on "plenty of times".

Just curious. Thank you.

 

Well, it's up to you whether or not you trade-in your Prius. However I'd like you to make your decision based upon a correct understanding of the warranty coverage.

The hybrid vehicle ECU, traction battery ECU, inverter, and traction battery are all covered by the hybrid system warranty which is for 8 years or 100K miles, whichever comes first. Check your Warranty and Scheduled Maintenance book to confirm this.

It is true that the hybrid vehicle ECU is also covered by the Federal emissions warranty for 8 years / 80K miles, but the hybrid system warranty provides better coverage so that warranty dominates.

Since you mentioned moderate ambient temps, are you in the Flagstaff area?

I haven't heard positive reports regarding Phoenix dealer service. My personal experience has been that Precision Toyota in Tucson does a good job.

I also hear the traction battery fan come on from time to time and consider this to be normal behavior.

This past weekend I drove the 2007 up to Mt. Lemmon, and that was a good workout for the car. Maybe you should repeat the road trip that you took which caused the failure, to see if you can get the failure to recur.

 

Hi DJ,
Have you had any issues with the 12v battery?

I had occasional VSC lights on my 2005 when the HV Battery was fully charged. Then I started having 12v battery issues when the car was not used for a while or if I left a door open for a while. I replaced the 12v battery with an optima and all the lights quit happening.

The 12v battery needs to keep all the computers working during the boot up process that happens from the time you push the power button until the DC-DC converter comes on line. If the 12v drops low for a short period of time you can have a computer that may seem to be working but did not really boot up properly. Later while you are driving this computer can cause problems.

I would suggest checking the 12v Battery just to be sure.

Thanks,
Dan

 

Save the work ticket. It will document that you reported the problem at under 80K miles. If it occures again, that would set the mileage, not the mileage at the time, assuming it is not years later.

 

Thank you. Just one more question please? My car has never seen a hill in its life. Have never heard the battery fan come on and see one green bar shy of all green everyday. Do you see solid (I think eight bars) green when thie fan comes on? I have never seen solid green.

Odd that the system will allow the charge to continue until the batteries heat up. Thats tells me that charge level is not an illegal operation its just another level of charge my car never see's. And it heats up the batteries. As you stated charging the batteries so much they heat up is not good for battery life.

My point is whats the difference in battery life in my car that never see's lets call it "super charging" but yet never heat's the batts up compared to your's and Patrick's car which apparently is seeing another level of charging.

I can sense your upset so don't answer if you don't want to continue this discussion I am just curious. Thank you.

 

Did someone say, "check the 12V battery"? Here are instructions:

http://priuschat.com/forums/newbie-forum/73400-weird-stuff-happening-mpgs-dropping-test-battery.html

 

Well this sounds really familiar!! I have been have the similar happen for the past year or so now.... The vsc light (!) goes off - system says pull over and reset the parking brake....as it simaltaiiously shuts off the A/C and switches the car into NEUTRAL!!! Not cool when driving at ANY speed!!!!! Let alone the couple times I was on the highway doing 55 and had to cross lanes of traffic with a car in neutral. Every time this happens I have reported and taken my car to the same dealer where I purchased (and have had service) it. The last time they had it they replaced 3 computers that they thought were miscommunicating to each other ( I got charged for two and they absorbed man hours and gave me a loaner car for the week they had it). After that it did fine until TODAY 5/24/12!! It did it AGAIN!!!!!! Now what ? I called them and they want me to bring it in again.... Yes again I will get a loaner but after already having spent $1800 I hesitate to see what the next round of educated guesses will do to my wallet. HELP ME SOMEONE PLEASSSSSSE

 

Your problem sounds different than the OP's. Did your traction battery go to all green then shut off? Your problem sounds like a weak 12v battery to me. I would not let the same dealer touch it. The chances of 3 ECUs (or computers as you call them) going bad at once is almost zero. It sounds to me they were taking potshots while troubleshooting your car (at your expense). Almost any problem you have can be solved here. I would check the 12V battery voltage. It should be above 12.4 when the car is off. If you aren't comfortable doing this, go to Autozone or similiar store in your area and have them do it. They will do it for free. Other than that, keep posting your symptoms here and we will attempt to help you.

Some other info may be helpful like:

What are your driving patterns (short, intermediate or long trips)?
How many miles on the car?
Has the 12V battery ever been run down to a very low charge?
Has the 12V battery ever been replaced?
Are you in northern, central or southern FL?

I am not an expert (I just think I am) but, Patrick Wong and Seilerts are. If they respond, pay attention!!!! I'll bet there is someone here that has experienced this problem before.

 

That is exactly what happened to me tonight! I am almost at 110K, 2008 - been feeling that "no acceleration feeling", then about 20 miles later, going downhill - slow-, the same lights came on, so I continued slow until the car stopped. I shut down 5 min - turned on - master warning, check indicator, wheels on display were gone, a little car with exclaim on the top of display panel - but was able to make it home.

Of course, on Sat I plan on driving to Arkansas - grrrrr...

Was it just the 12V battery or the more serious sounding ECU issue???

 

I suggest that you check the 12V battery (there are numerous posts on how to do that including one cited earlier in this string) and if you have any doubt, replace it now.

I also suggest that you make the Prius READY and look at the inverter coolant reservoir (mounted on the side of the inverter). Do you see fluid turbulence in the reservoir, which shows that the inverter coolant pump is working? If you do not see this, then the pump needs to be replaced immediately.

If you do not find any problems with the above two checks then I suggest that you have your car checked out by your local Toyota dealer or a competent independent who specializes in Toyota hybrids, prior to embarking upon a road trip.