2005 prius gas engine wont start

you need to pull the trouble codes. how many miles on her?

 

If some fault light has been on then there is fault code in the memory. Fault codes stay in memory until they are cleared with computer or 12V battery is disconnected.

 

There may be no codes for the engine, which may be in proper working order, but there will be for the other system(s) that failed. It sounds like a hybrid system problem. You need a Toyota scan tool or equivalent. Better check that new battery, too. What's the voltage at the terminals?

 

You can buy Mini VCI from many different places including ebay and amazon.

 

10min is enough; probably even a minute is enough. But why would you want to clear the codes without finding what’s the problem?

Mini VCI can do everything that dealer can. You do need Win XP laptop for it.

 

you need to charge or replace the battery.

 

+1 for "you have to pull the codes" before we really know what you're working with.

 

2004 gen II Code U0100 | PriusChat

That's the first result I got with I googled "prius code u0100", and it seems to fit the bill perfectly. I'd say an integration relay is bad, although someone more knowledgeable than me might know whether or not the symptoms/code you're experiencing could be caused by a different failure.

If I understand correctly, there are two integration relays in the Gen II Prius, FYI. It's a pretty rare part to go bad, so you might be fine just replacing the broken one. The parts themselves aren't too expensive though (~$115 each). If you wanted to replace both, I'd bet it will be somewhere around a $400-$500 bill including labor.

 

While you are waiting to receive your parts, I suggest you put a charger on the 12V battery since 12.1V is close to a discharged condition.

 

After reading several posts and replies, it is clear that there are a lot of smart Pruis owners or guys/gals who can just figure things out.
I have a technical question, that I would appreciate some feedback on with my 2005 Pruis.

In Brief:
History: Appx 254k, replaced 2 battery cells about 12 months ago (Oct 2014). Was able to restart car and has been running at 47mpg until this week.... another cell went bad as I was well aware of the symptoms.
Today (Nov 2015): Appx 286k, one cell at 7.1 v, all others at 8.1 or 8.15 v. I removed the one cell and replaced it with a spare that I still had from 2014. The replacement cell was 7.4 v (Appeared to be within spec) but not equivalent with the other 27 cells at 8.1v.
Problem: After reassembling the unit with replacement cell, and installing, the car will not start. Lights are still on and do not go away. Even when resetting codes by using meter. I am not sure if there is a special sequence or procedure that must be followed to restart or reboot the computer after replacing the battery pack.
Here is what I have tried after trying to restart several times.
- Battery Pack reads 217 VDC at power connectors on battery side of switch. All connections including safety plug appears to be in order
- Verified Codes have been cleared. by using code reader.
- Battery (12Vdc) , positive and negative removed for over 20 min to ensure that the computer will reset. 12vdc Battery appears to still be in good shape reading 12Vdc.

Same problem....
Even if the batteries were not perfectly re-balanced, wouldn't the car start? Even with the error codes?
What do you recommend is the best course of action at this point? Is there a power up sequence once you replace the battery pack? Should I replace that 7.4v cell with a cell that is 8.1v to match other 27? It appears that the delta voltage is very critical.
Does the bottom side wire on the 28th cell (my 7.4v cell) control the starting of the vehicle?

Any feedback would be appreciated.

 

Yes, the module pairs need to be within 0.3V of each other. If they are not, then the traction battery ECU will log a fault code and the car may not start.

The best course of action is to buy and install a new traction battery.

The cheapest course of action is to make battery module replacement a hobby, which is what you have started to do.

 

Yes, Patrick.... If I only had a $1 for every time someone told me to give it up.... I just have to find the solution to this puzzle.
Thanks for your prompt response and information.
I have already ordered the replacement module, but with my impatience, I used the extra one on the bench that I bought from last year, even at 7.4, I thought I would give it a try..... So I found my answer..Thanks.

I looked up where the ECU is located. thanks.
In parallel, I think I want to try two things.
- research the appropriate method of recharging of the three cells I have. i.e. Create a diagram with an appropriate power source as well as battery cell hookup.
- Install the replacement module that should be within the 0.3 v spec that you mentioned.

So, there is no trick to restarting after reconnecting the 12v battery and the safety plug?

Thanks again, you have been helpful.
Bob

 

does the car become ready when you power up?