BRZ spontaneously won't start
 

I've been having this issue for a few months now and have finally narrowed the "symptoms" down as much as I can. Basically about 50% of the time that I go to start the car it won't start. I have keyless entry and push button start, and when I push the clutch in (all the way) sometimes the "green key" indicator simply won't show up on the dash, and the car won't start when prompted. Sometimes the green key pops up immediately (solid) and the car starts just fine. I'm assuming there's some problem with the clutch and the electronic path which shows the clutch is being depressed to allow the car to start, but I can't purposefully demonstrate it as the car has a mind of its own in this way. Any ideas what's going on? The only way to "fix it" when it gets like this is just mess with the clutch for a good 5-10 minutes and then miraculously it'll show the solid green key and then start like usual. I've had the car for 2 years and this just started relatively recently.

Oddly at first I thought it was some problem with the battery and took it to Autozone and they found a problem so the dealer replaced the battery, but it didn't help the starting problem at all.

There is a switch that gets depressed by the clutch pedal itself which tells the car you are pressing the clutch. The first thing I'd do is peek under there and make sure that switch is properly adjusted. You can look around on the forums for photos. Find a DIY thread for adjusting clutch pedal height (or spring removal) and it should have a picture of it.

if its still under warranty. Take it back ASAP

Have you checked the battery of the key?

I popped my head down there the other day and couldn't find it but I'll look online, thanks.

I have not. Maybe I'll start using the other key and see if it stops.

It is and I already did but they were just as lost as me but I've narrowed the problem down more. They just replaced the battery which didn't help (odd coincidence that it was also dying?). I will take it in soon if I can't fix it as I have another 9 months on warranty I believe.

So I'm watching this video and was down there for a bit and couldn't find anything that might be the problem (not sure what I'm looking for). I tried a new key and it did it again.[ame="https://www.youtube.com/watch?v=ScZFQ0j5beY"]BRZ/FR-S Clutch Pedal Adjustment DIY - YouTube[/ame]

Does the door unlock from the proximity of the key? Does all of the interior stuff come on when you hit the start button but the car not start?

What color is the key icon when the car doesn't start? Is it yellow?

Does jiggling the steering wheel have any affect on the car starting?

What you're describing almost reminds me of the thread below.
http://www.ft86club.com/forums/showthread.php?t=109052

Key works fine for everything. All lights and everything works when I hit the button. The car will NOT start unless the "green key" in the dash is solid. When it does NOT start there is NO green key, there is no yellow key, there is nothing to signal anything. It's like I'm not pushing the clutch in basically. You'll notice on a "normal" BRZ the light will turn on solid when you engage the clutch. I don't know how I get the "green key" to show up. Sometimes it seems like I get it from messing with the wheel or the shifter or the clutch. It seems so hard to replicate it and even harder to fix when it happens.

The guy in that thread seems to have a different problem as his "green light" prominently showed while mine wont.

clutch safety switch. Adjust the clutch down a little and see how it goes. If that doesn't fix it, adjust it up some and see if that fixes it.

the switch could be bad too, but most likely it is just out of adjustment. Grab a wrench and fix your problem.

Where's the switch? Down there by the clutch? I just don't know when the problem is gonna happen so it's hard to tell if moving the clutch around will fix it or not since it's sporadic. It's been hot as hell here (over 115) and I wonder if it's caused some issues with the switch/electronics because I've never messed with the clutch.

Well for prosperity's sake here's what the switch looks like (I think?)
http://www.rockauto.com/info/903/1S14060.jpg

have you made sure that your steering wheel was not locked prior to starting up the car? with your steering wheel locked, you will still have power to your accessories but just the starter won't turn I believe. some people would accidentally bump their steering wheel when getting in and out so they do not realize they locked it up.

I would replace the battery in the key before getting a wrench anywhere near the car. That may not be the problem, but it's really cheap and easy to rule it out. It would be really stupid to start mucking with other stuff only to find out in the end that it was just a tired key. Generally, when troubleshooting, you rule out the easy shit first.

This^
Read pages 79 and 167 of your owner's manual.

I thought the same thing at first but the OP said in post #6 that both keys are doing the same thing. The key is also unlocking the door and turning on all of the ACC power and internals, just no juice to the starter.

I was thinking either steering wheel lock or clutch switch.

It's never locked when this happens. It happens like 75% of the time when I start it and is a new problem.

Still happens with new car battery AND new key. I have no desire to mess with clutch and am 93% sure it's the clutch safety switch.

A new key with a new battery, or the spare key that came with the car, which has been sitting for two years?

That brings up an interesting question I don't think I've seen asked or answered here. The key fob on my Jeep doesn't transmit anything until you push one of the buttons. The rest of the time, it's completely inactive. If you push the buttons more often, the battery will die more quickly. The battery in that fob lasts several years.

My BRZ key is different. It works whether I push any buttons at all. I can walk up to the car, open the trunk to stash my bag, open the driver's door with the switch in the door handle, start the car and drive away without ever touching the key at all. The battery in it died a few months ago (and behaved similar to the way you have described, but only for a day or so before it died altogether). It seems to have a much shorter life span than the one in my Jeep key.

Is the BRZ key inactive until the car senses it, at which time the car tells it to start transmitting? Or is the key always transmitting a low power signal for the car to detect? Based on the short battery life, I suspect it's the latter. That would be a lot simpler design, and a low power transmitter can certainly run for a couple of years that way on a wafer battery. I don't think the key is smart at all. It just sits there spitting out a signal without ever knowing it's near the car.

If that's the case, that means your "new" key is not new at all. While your "used" key has been transmitting for the last two years to open and start your car, your "new" key has been transmitting for the last two years to the inside of a drawer, draining the wafer battery at the same rate.

So again, regardless of whether you're 20% or 50% or 93% or 99% certain it's the clutch switch, I suggest you go buy a new battery and see if it fixes the problem. If I'm wrong, you're out six bucks and a trip to Best Buy. If I'm right, you saved yourself a lot of time and irritation fucking around with something that isn't broken.

I have been experiencing this as well. I have to clutch in multiple times for the green key indicator to show up and then it will start.

if you think it's the clutch safety switch, have you tried to fix it? maybe the spring mechanism on the switch is getting stuck due to excess dirt or something. I haven't heard of anyone having their clutch switch breaking, but there is always a first time for everything.

I've put my head down there but I can't really find anything out of the ordinary though I have no clue what I'm doing. I can't find the switch.

I've been stranded for 30-40 minutes a few times because of it. It just randomly miraculously works after awhile.

edit: I got an appt for the 29th which is as early as they could get me in when the "main tech" guy is there because this issue apparently is confusing them.

I think you're more looking for this part...

http://www.rockauto.com/info/154/NS1...%20primary.jpg

I would just make sure that it's plugged in securely and that you can depress the plunger.

It's possible that the lock nut has backed off and the plunger is not being depressed all the way / far enough.

Since you're still under warranty get it back to the dealer and get them to work it out. ***** Nevermind, just saw that you have an appointment.

yup, that's the one.

heads up! There are 2 of them, one in front of the pedal and one behind the pedal (with respect to the car, nose=front tail=rear). you want to check the front one.

Here's the info on the clutch switches from the service manual. There are TWO switches, a clutch switch and a clutch start switch.

http://i315.photobucket.com/albums/l.../cl-00951e.png

REMOVAL

1. Disconnection of battery ground terminal
2. Removal of instrument side panel RH
3. Removal of instrument panel under cover SUB-ASSY No.1
4. Removal of instrument panel under cover SUB-ASSY No.2
5. Removal of knee airbag module
6. Removal of clutch switch ASSY
(1) Remove the clutch switch connector.

http://i315.photobucket.com/albums/l...Remove%206.png

(2) Remove the nut and then remove the clutch switch ASSY from the clutch pedal support SUB-ASSY.
7. Removal of clutch pedal support SUB-ASSY (refer to )
8. Removal of clutch start switch ASSY
(1) Disconnect the clutch start switch connector.

http://i315.photobucket.com/albums/l...Remove%208.png

(2) Remove the nut and then remove the clutch start switch ASSY from the clutch pedal support SUB-ASSY.

INSTALLATION

1. Installation of clutch start switch ASSY
(1) Install the clutch start switch ASSY to the clutch pedal support SUB-ASSY with the nut.

Standard value:
Tightening torque=8.0N·m { 82kgf·cm} {5.9ft·lbf}

(2) Connect the clutch start switch connector.

http://i315.photobucket.com/albums/l...nstall%201.png
*a - Clearance

(3) Measure the gap shown in the figure with the clutch pedal fully depressed.

Normal clearance : 3.5 to 4.0 mm {0.138 to 0.157 in}

2. Installation of clutch pedal support SUB-ASSY
3. Installation of clutch switch ASSY
(1) Install the clutch switch ASSY to the clutch pedal support SUB-ASSY with the nut.

Standard value: Tightening torque=8.0N·m { 82kgf·cm} {5.9ft·lbf}

(2) Connect the clutch switch connector.

http://i315.photobucket.com/albums/l...nstall%202.png
*a - No gap

(3) Check that a gap is not created when the clutch pedal is not depressed.
4. Installation of knee airbag module
5. Installation of instrument panel under cover SUB-ASSY No.2
6. Installation of instrument panel under cover SUB-ASSY No.1
7. Installation of instrument side panel RH
8. Connection of the battery ground terminal

Standard value: Tightening torque=6.0N·m { 61kgf·cm} {4.4ft·lbf}

9. Settings when removing/installing battery terminals
10. Check of airbag warning light

ON-VEHICLE INSPECTION

1. Check of clutch start switch ASSY
(1) Make sure that engine does not start with clutch pedal not depressed.
(2) Make sure that engine starts with the clutch pedal fully depressed. If necessary, replace the clutch start switch ASSY with a new one.

UNIT INSPECTION

http://i315.photobucket.com/albums/l...nspect%201.png

1. Check of clutch start switch ASSY
(1) Measure the resistance between terminals when operating the shaft.

Captions in illustration
*a - 4.0 to 5.5 mm {0.157 to 0.217 in}
*b - ON
*c - OFF

Resistance
When shaft is pressed in (ON) - Less than 1 Ω
When shaft is not pressed in (OFF) - 10 k Ω or more

Awesome thanks everyone.

In case anyone is confused...

The switch that the clutch pedal arm touches when you depress the pedal all the way is for engine start.

The switch that the arm touches in a natural resting position is to disengage cruise control if you have it on.

-alex

Yes, but which one is which?

Clutch start switch is the higher of the two, that one is for engine start.

-alex

The switch at the top of the clutch pedal travel is for detecting the clutch is fully released. As above as you start to press clutch it trips and will disengage cruise control and on manual cars the gear indicator will turn off.


The Switch at the bottom of clutch pedal travel is for the start inhibit, if clutch is not to floor to activate the bottom switch car wont start.


Unplug switch and measure with multimeter, you should be able to bypass it by either unplugging it or looping the connector depends if its normally open or normally closed operation.

Well now I feel bad. I was just trolling mav.

So I finally found it and I noticed one thing: when the clutch is fully depressed it only pushes in about 2/3 the plunger.

On second thought maybe the switch IS bad because I just noticed this post:

So I assume that gap is normal. Maybe the switch is just going bad because it still works sometimes. I'll leave it up to the dealership I guess but I don't think I'll leave without them having ordered the part.

make sure you point it out to them which switch is bad, otherwise they might replace the wrong one lol.

Gonna bump this as I've been having the same issues.
@pevsfreedom how did you end up fixing this? Did the dealer fix it, and if so what was the issue? Hoping to figure out if its just a misalignment or if they had to replace the switch.

Pull the connector and jumper it. I bypassed mine long ago for totally OCD reasons.

Thinking bout doing that. But kinda worried about dumb parking valets that dont realize the car is MT before hitting the button.

Whoops, no way. Don't even consider it. I wouldn't do it myself if I had pushbutton start.

Didn't think about that. :bonk:

I got mine fixed at Subaru. They replaced the clutch switch and the battery and now it starts every time.

I think the bigger issue is that you allow people to valet your car :confused0068:

I had to do it once at a ritzy hotel. It was truly painful. After chastising him for slamming the door shut (I demonstrated by pushing it closed with one finger) he let me keep it in the staging area.

Hard to avoid in NYC. A lot of the parking lots here use valets. Even at my own parking garage, they let you park the car yourself but they keep a spare key in case they need to move it because a lot of the cars are double parked.

I'm gonna take a peek at the switch and see if i can just adjust the nut a bit. If not, I guess I'll go to the dealer.. sigh.