2002 Prius start up problems

I appreciate your effort to provide a lot of details with your post, but really it would be quicker and most helpful to give the details that matter most, which are the trouble codes stored in your car's computers. Without those codes, we would only be trying to guess from the lights on the dash and your other description. Because there are only a few lights on the dash to alert you to hundreds of possible trouble codes, you can't really think of the lights as telling anything more than "something is wrong, read the codes".

There are only a few reader options that work with a Gen 1 Prius. A lot of people are going Mini VCI, very inexpensive if you have a laptop already to hook it to. ScanGauge II or (as far as I know) the Torque app for a phone can work too, but for both of those you need to look up or download special configurations to talk to a Gen 1 Prius.

Hope this helps,
-Chap

 

Unless you have left out a lot of important detail, I don't think you have found the problem at all -- you have just found a way around the problem.

Like Chap said, you really need to pull the codes and tell us what they are, if we are to have any chance of helping you.

It is not normal to have to wait 20-30 sec after putting the fob in the slot before you start it. If it works and you are happy to do that then I guess good luck to you. I suspect, though, that it won't be a long term solution.

 

Well you know what they say: You can lead a horse to water but...

 

Oh great to read. Thanks for keeping us posted.

Yeah, CCA on a older battery will dwindle over time. Highly recommend a battery tender if you want that old battery or for that matter a new one to last longer and start every time.

 

Read the '12v' threads. Basically, Prius has parasitic drains, as do many cars these days. But the Prius 12v battery doesn't have that large of an Ah (kwh) rating. The older it is, the less Ah and perhaps V it has, too. The colder it is, the less Ah it has, and loads will drop the V faster. Turning on the car to start it, which is shortly after the interior lights have been lit up, causes various relays to pull in, and several devices to start running (processors, ventilation fan, etc), and pulls the voltage level down. There is already a significant enough voltage drop from the battery to the front-of-car equipment. Things like the MAF sensor and processors don't like voltage brown-outs, then you ask them to function normally right away by starting the engine.

Personally I wish they had connected the DC-to-DC in before the engine start, so turning the key to On position would turn the DC-DC on. I believe it doesn't engage the DC-to-DC until after the engine starts. I'd rather the DC/DC get turned on, then sequence through all the rest of the loads/needs as usual, and when the key is in the start position then turn the engine over when needed.
I've never had a low traction pack at engine start, which is their concern - the DC-to-DC will draw an inrush current and an additional load after that to drive the 12v system up to 14v. They're rightly worried that you might not start the car soon enough, and if the traction pack goes too low the recovery is a lot more effort than recharging/replacing the 12v. Wonder if anyone has modded their car to pre-enable the DC/DC...

 

That would be cool ^^^ and more logical

 

I have been having similiar problems with my car. In the morning when you turn it on, the engine starts for about 10 seconds,
and then shuts off and the death triangle turns on. The car still operates in electric mode. If you shut it on/off a few times,
it will start the engine again and work normally. This has progressively gotten worse and worse, and now it does it pretty much every morning.
I read the code which was 'engine not ready'. I worked around it for a while by immediately accelerating the car once it started,
but even that doesn't always work now. It has no problem when its warm.

I'm thinking it must be some sensor, but don't know which one it could be? I really can't ignore it anymore, and must find a fix.

 

What scanning tool did you use and what code did it report? The symptoms you describe match those I experienced which were reported by Techstream as P3191 - Engine does not start. Like you I was able to get around this for a couple of days by accelerating once started. I also noticed it wasn't a problem when warm.

I took Bob Wilson's advice and cleaned the throttle body, which turned out to be an easy job to wipe away a good buildup of carbon and gunk. This nailed the problem and the car has been running well since.

 

Cleaning Prius Throttle

Bob Wilson

 

+1 what Dr Bob suggests

 

I cleaned it about 12 months ago. How often do they need cleaning? It wasn't too bad when I did clean it.
I'm quite curious why this would make the system think the engine was not running.
What is it using to determine if the engine is running?

 

1. I do it when changing the oil. But I suspect it is a question of the quality of the local gasoline.
2. When starting, the engine initially takes torque from MG1 but once it starts running, MG1 torque reverses as the engine begins spinning MG1.

Good luck!
Bob Wilson

 

Bob
I have been restoring or better to say resurrecting a 2001 prius that sat for 3 years that I bought cheap off of Craigs list. After 3 months of clearing the problems it had, bad cells in hydrid battery, corroded connects to the hv bat ecu, fuse box that was tampered with disrupting power to the engine cpu, plugged hv pump on inverter, mice in heater system, and key problem. I got the car running and drives nice. The last problem that has given me intermittent trouble is the valet key. I tried the suggestion of mounting the key in the immobilizer detection coil under the dash. Made new keys from the valet key and car starts. My question is getting the ready light to come on when first starting. It will only come on after cranking the engine. Sometimes the service light stops the process so I have to repeat the start. I notice the multi-display goes out when starting, is proper. I would appreciate your thoughts.

IKE

 

Correct the problem of key not flat against immobilizer coil, starts clean every time now. Display does go out when starting per the manual.
Ike