Prius don't start

I assume you are pressing the brake pedal when you push start. If you are doing that and it doesn't go into Ready, the most likely problem is the brake pedal switch. There is a little switch on the brake pedal arm that senses when the pedal has been pressed. If this switch fails or the connection is loose you cannot get into Ready. Try wiggling the wire. If that doesn't work, you may need to replace the switch.

Tom

 

What year? You don't "press start" in a 2001, maybe your
vehicle info is out of date..
.
_H*

 

Good point, hobbit. I jumped to a conclusion that it was a newer model.

Tom

 

How's the 12V battery? That can give some scary results when it can't hold proper voltage. Shouldn't be bad on a 2007, but at least check the cable attachments, maybe put a voltmeter on it (in the back of the car, on the right side of the trunk).

 

When I went to purchase my Prius the exact same thing happened. The guys were imbarrassed. I knew the 12V battery was dead. Past a certain point it can't be jumped and the car won't go into park. Best guess 12V is nearly dead and won't accept a charge. Best of luck!

 

In post #2 above, Tom suggested that the brake pedal switch is the most likely suspect if in fact you have a good 12V battery. I agree with this. Press the brake pedal down hard and forcefully when you try to start.

When you turn on the headlights, do they light at normal brightness or are they dim? That is a quick way to check the battery. If the lights are dim, then the battery is weak.

If you have a digital multimeter, you should be able to read ~12.6V across the battery. If voltage is much lower than that, then the battery is discharged.

 

Or could be a problem with the alternator?

 

Hi Jorgeez,

The Prius does not have an alternator. It has a 200 volt to 12 volt DC converter (very similar to a personal computer power supply in circuitry, but integrated into the inverter assembly). If the main battery is has good state of charge, the DC converter will charge up the 12 V battery.

 

I have a 2002 Prius that won't start. Had it towed into a dealer that changed the 12V batt. then told me he didn't know what else was wrong but if I paid another $300 he'd figure it out but he thought it would be the hybrid control unit or the enging control unit. The uncertianity made me nervous and I just had the car towed to my home. I am now looking for Electrical system wiring diagrams, and a code reader. Any suggestions? BTW I've been a bit of a gear head since the 70's and I'm an electrical engineer so I've got some ideas how things should work. Given the car ran fine and just fail to start, I'm thinking something on the order of a netural switch (if the Prius has one) or some equivilant. Whne the car fail to start. I still had headlights, power windows and other 12V functions so I didn't really beleive the 12V was bad. I asked for the old battery to be returned to me but of course it wasn't. ANother reaso not to continue with that dealer.

 

What warning lights are on? What is the odometer reading?

You can buy paper manuals for ~$300 or you can subscribe to techinfo.toyota.com and download .pdf files (but note that this is a very tedious process.)

I'd expect a Toyota dealer service dept to retrieve the DTC, let you know what they are, and provide a tentative diagnosis for a one hour labor charge. I suggest that you find another dealer to visit. Or you can try buying an OBD-II code reader but there's no guarantee that the code reader will successfully retrieve all logged DTC since multiple ECUs can generate them.

In general, with a engine no-start problem, I suggest that you first address the basics: replace the iridium spark plugs, make sure the engine air filter is clean, clean the throttle body and throttle plate, and make sure the engine oil is not overfilled and is the correct 5W-30 viscosity. If the engine still does not start, TSB EG011-03 suggests replacing the engine ECU; the current revision ECU has part number 89661-47054 and allows more time for the engine to start before logging a DTC. I've provided this TSB in other postings, pls do a search if you are interested. The engine ECU is located behind the glove box, if you examine the old one you may be able to see the part number, or you may have to remove it to view the label.

You can probably buy this ECU from a salvage yard for ~$300 or so. A new one would cost close to $1K. Good luck.

 

Even if the car had an alternator, it would not be involved in starting the engine.

I'm a noob to the Prius, but not to cars. I'd check the 12v battery first and then the brake switch. I would also assume that the brake lights are triggered by the same switch. See if you can tell if the brake lights are coming on when the pedal is depressed.

Check the battery first, just to rule it out.

 

I've gotten My 2002 Prius started. Yea. and many thanks for all the posts here that gave me ideas. To answer the questions from Patrick. Warning Lights, I don't remember. I borrowed a OBDC II code scanner form a friend. When I connected it the car started. The MIL was on. Code scanner reported a P1636 - ECM (ETCS Circuit) as the only code. After reading some of the posts here I decided time to change the plugs, air filter and clean the throttle body. This car has 142,000 miles and the plugs were orginal. Ran great for several days. My son took it back to school to get some stuff. Round trip aprox 50 miles. When he got back the MIL was on again. This time the code was a P0420. I cleared the code again. I drove it for several days No problems. I put about 150 miles on the car. Then I had to let it set a couple of days. My daughter picked the car up to take to my son and had it fail to start when she stopped to get coffee at a shop about 2 miles from home. I had her try the on-off-on-off-on-start and the car started and she brought it back home. MIL on. Code P1636. I dumped the Freeze data.
Code P1636 ECM - ETCS Circuit
Fuelsys1 OL
Calc Load 0%
ECT(F) 132
STFT B1(%) 0
LIFT B1(%) 2.3
Eng RPM

 

I will continue here
Eng RPM

 

It will help if I could type...
Eng RPM 0
Veh Speed 0
IAT(F) 64

I've cleared this code and took the car for a 10 mile drive. It took awhile for the O2 and CAT monitors to complete their tests. "EVA" monitor did not complete. I don't know yet what "EVA" monitor is. So not sure if I have to do something specific to get it to complete. I am very nervous about sending this car to school with my son. It's already cost me over $600 at the afore mentioned "dealer" that I will never trust again. I hope someone can point me in the right direction. I haven't yet measured the HV batt voltage (although I can when the weather clears). I don't like the idea of working near 200+ VDC in wet weather. Quick way to end one's life!

 

DTC P0420 "Catalyst System Efficiency Below Threshold (Bank 1)".
DTC P1636 "HV ECU Malfunction".

I agree that it would not be a good idea to release this car to your children to drive until the problems have been identified and resolved.

I sold my Classic repair manuals when I sold my 2001. However, P0420 means that the catalytic converter is bad. (If you replace oxygen sensor #1 with a new Toyota part, the warning may go away for a while. The engine ECU is quite sensitive to a marginal catalytic converter, and a new oxygen sensor #1 will demonstrate more responsiveness to changes in oxygen content as the engine ECU cycles fuel/air mixture from rich to lean while in closed loop operation.)

P1636 means that the engine ECU thinks that the hybrid vehicle ECU is bad. This is not a common DTC, I suggest that you download repair manual info from techinfo.toyota.com to determine the recommended troubleshooting path. If in fact the HV ECU is bad, you can probably obtain one from a salvage yard for $300 or so.

Here's one website that indicates P1636 was caused by a marginal 12V auxiliary battery, so if that battery has not been recently replaced, you may want to consider that as well.
http://cdlautoparts.co.nz/index.php?option=com_content&task=view&id=28&Itemid=6

BTW, pls note that you can edit your posts after they have been created. So you don't have to send three consecutive posts (unless you want to.)

 

I would subject the battery to a load test, not using the car.
I think you will find your problem. Optima upgrade.