"P LOCK MALFUNCTION: WHEN PARKING, PARK IN FLAT PLACE..."

So.....out of curiosity, did you check your 12v? I saw a video posted on the site recently that showed Luscious Garage explaining the same thing. Seems to make sense to me. Faulty/weak 12v = inadequate power for starting up and keeping the electronics functioning correctly.

 

this one can be difficult. maybe a door not fully closed, all the way to a high voltage leak. did tech stream produce any codes?

 

testing the 12v battery is easy, or just replace it if original. but if you can't do that, a dealer would be your best bet.
how many miles on her?

 

Were you able to find out the issue? My car is doing the exact same thing.

 

We had one similar issue in 2011. It ended up being wire pinched and grounded right off the fuse box and also fuse was blown. I would check good under the hood and fuse box area.

 

SOLUTION for a car that doesn't have any other problem:

If your battery drains (maybe you forgot a light on) this problem might appear. Disconnect the battery entirely (I mean either the + or -, I read from a Toyota mechanic that you need to disconnect in order to reset/wipe some codes/warnings in the computer). Reconnect, boost the car and it should start unless there's another problem (like mentioned above, cables shorting and whatnot).

Andrei

 

I have a 2010 Lexus HS250h with 200k miles on it. Today I experienced the same issue on a vehicle that has NEVER had any problems. I assumed the problem was a weak battery so I tried to jump it with my other car...after about a half hour of charging it, no luck. Then I hooked it up to a Diehard battery charger which connects to a power outlet in my garage. In less than a minute, it solved the problem completely. The car immediately turned over and all systems were functioning normally. I know NOTHING about cars, but I think it may be possible that the steady 120v current from the Diehard could have reset something in one of the computers. I’m not sure if this qualifies as a solution, but I thought I should share it with anyone who might be interested.

 

So this just happened to me today after using the Accessory port to try and run a tire air compressor to fill it’s tires. Apparently the battery is super easy to drain this way and it threw that P Lock error and wouldn’t stop making a humming noise. It was chaos and the worst part is it was the lady’s car. Anyway, i explained to her it was probably as simple as the battery being drained but she was flipping out (she’s an electrical engineer who builds satellites lol ) . I told her I’d call AAA and they’d be able to probably jump it no problem abc then charge it up. She kept saying she wanted AAA to replace her battery with OEM, which I explained they don’t do. Lol anyway, long story short they ended up coming jumping it and works like a champ. So this error is likely just the battery’s way of telling you it’s tapping out

 

Old thread, but this is what worked for me. My battery had died and I did a jump start/recondition. When I turned the car on I got the p-start malfunction error. The car did actually turn on. When I went to check the fuse box, I noticed the lid was not on all the way. After checking the fuse and securing the fuse box lid on all the way, I restarted the car and the error went away. Perhaps there is a sensor that can tell if the lid to the fuse box is not on all the way

 

2009 prius 120K miles. Bought used, has it inspected, all checks good. Drives fine for thousands of miles, took it for a recent 15 min drive, turn it off. About 5 min later, I came back and won't start, all lights flashing on dash, full gas tank shows 1 bar, won't shift, eventually all squares in the drive/park/reverse grid on the dash flash the borders and then engine check light comes on and also the triangle.. Try two more times to start, same result, lthe second time lights eventually stop turning on , car acts like 12 v battery is dead. Go to jump the car, car turns on and the middle screen says " "There is a problem with the transmission "P" lock mechanism Park your your car on a flat surface and fully apply the parking brake." While the car is running, I fully push the parking brake down, let it stay there for a few seconds and press it again to release. We removed the jumpers, I turn it off, try to restartt car goes back into fail mode, redo the jumpers, turn the car back on and then depress the parking brake fully, wait a second, release. And the car works. Ran an ODBI scan after it was running and no problems noted. This has been a reliable car, not sure what to make of the problem or the fix, but the car appears to know what was wrong and knew the message to display to fix it. Not sure why it took a jump to get there, can't say if this is a fix for all, but it worked this time.

 

2013 Prius II. After a snowstorm, I parked close to a curb and slightly up on it because the snow was so high, I couldn't tell where the curb started. Once I realized the right front tire was up on the curb, the car was already turned off. So, I pushed the Start button, and got this message: "P Lock Malfunction When Parking, Park In Flat Place And Apply Parking Brake Securely."

I put the car in Reverse to move it off the curb and got this message: "Shift to P Position When Starting". I pressed "Start" to turn the car off and it would not fully turn off. When, I pressed "Start" again, the "P Lock" message came back. Emergency brake was secure and the car was in Park the whole time.

I went in the house for about 10 minutes to Google the messages and came across this Prius Chat forum. Before trying to start my car again, I first opened and securely closed each door including the hatchback. I pressed the Start button again and the error message was gone. Not sure if the error went away because I let my car alone for 10 minutes or if it was because I opened and closed the doors before trying again...or both. Note, I've never had this problem happen before.

 

That solution worked Thanks even Toyota did not know how to fix it when I called
I hate it when cars get so complex that a little problem has you running around and you need to go to school just to know how to fix simple problems.

 

I was wondering if you found any solution to your problem. I am experiencing something similar, p lock error on the dash, won't start, the battery is good.

 

Try this.

Put the e-brake on all the way. Turn on the car by pressing power twice (don't start). Put the car in neutral. Then start the car. Let us know if it works.

 

Toyota and Lexus Vehicles:

“P Lock Malfunction
When parking,
Park in flat place and
apply parking brake securely”

This error most commonly happens when the small 12 Volt starting battery has been drained below the 12.5 volts needed to start the engine.

A faulty or weak 12v battery = inadequate power to start engine or keep electronics functioning.

Solution:
1. Place a charger directly on the 12V battery.
2. Disconnect the positive wire or negative ground for 5 minutes to reset error codes and electronics.
3. When battery shows over 13 volts.
4. Reconnect battery.
5. Start engine

> Placing a jumper wire in the fuse box is a stopgap measure because low battery power causes corroded wires to fail to transfer sufficient current.

They will work again when the battery is charged.

Sooner or later you may need to remove the fuse box and polish all wires and connections.

All Electric Vehicles have corrosion problems wherever there are bare electrical wire or copper surfaced components. Polishing them and using Carbon Conductive Grease or Corrosion Inhibitor Spray will prevent corrosion.

Do not use dielectric grease between connections!

It is an insulator!

Patrick Perry
A Worm’s Tale®
Salt Lake City Utah