2009 Forester Issues

Fireproof13 · 03-24-2018, 04:50 PM

Our forester is having some serious trouble, it's something electrical and after speaking with multiple people at the Subaru dealership I have gotten nowhere.

I can't figure out why the throttle body is doing this. Every other time you start the car it will do this:

Youtube clip of the sound.

If you turn the key back off and on, it will start right up no codes. The next time you start it it will not make this sound, start right up and throw a crankshaft position sensor code. P0336.

I tried replacing the throttle body with no change. The only thing I can think of now is the ecu, please tell my why it isn't. We pulled the ecu and checked it over and there is nothing visibly wrong with it.

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HudsonBrown1 · 03-26-2018, 09:00 PM

Im assuming that it is an etb (Electronic Throttle Body) if so it sounds like the motor is gone bad and its just going haywire, I would just replace the entire assembly you can probably get a used one off eBay fairly cheap.

Fireproof13 · 03-27-2018, 09:09 AM

Unfortunately that is the replacement throttle body doing the exact same thing.

We finally decided to let the dealership take a look at it and it seems that we may have found the problem. The crankshaft pos sensor should sense 30 teeth on the crankshaft sprocket and it is only sensing 29. We don't know why it isn't sensing one of the teeth, but I ordered a new sprocket and I'm gonna start with that. The mechanic explained to me that all of our symptoms make sense for this issue, so it seems that we at least have a lead on the problem. I'll update when it's fixed.

I was a bit skeptical that the sound that the throttle body is making could be related to a crank pos sensor issue, but the mechanic assured me that it is part of a self diagnostic that the computer runs through after clearing a crankshaft related code.

CosmoTheCat · 03-30-2018, 02:27 AM

The ECU runs a throttle body sweep after you shut the key off. When you clear the memory, you erase the learned stops and it has to redo the sweep before it will allow the engine to start.

Fireproof13 · 04-06-2018, 04:20 PM

The issue has finally been resolved! Turns out that the crankshaft sprocket had a broken tooth. I put on a new sprocket and it's good to go!

Charlie-III · 04-06-2018, 05:07 PM

Quote:

Originally Posted by Fireproof13

The issue has finally been resolved! Turns out that the crankshaft sprocket had a broken tooth. I put on a new sprocket and it's good to go!

Thanks for closing this out.
Glad it's fixed.

How the FRIG did a tooth get broken off?
Was a timing belt done recently?
Was this vehicle in a front end collision at some point?
Do you have steel eating rodents by your house?

wtdash · 04-07-2018, 01:18 PM

Quote:

Originally Posted by Charlie-III

Thanks for closing this out.
Glad it's fixed.

How the FRIG did a tooth get broken off?
Was a timing belt done recently?
Was this vehicle in a front end collision at some point?
Do you have steel eating rodents by your house?

+1000

IanT-EJ22 · 04-07-2018, 02:28 PM

Thats crazy. I don't have alot of experience owning cars with ETBs but it does make sense that the ecu would have some self diagnostics and fail-safes built in.

Charlie-III · 04-07-2018, 03:17 PM

Quote:

Originally Posted by IanT-EJ22

Thats crazy. I don't have alot of experience owning cars with ETBs but it does make sense that the ecu would have some self diagnostics and fail-safes built in.

I believe the OP was talking about one of the timing fingers on the crank gear.
I will guess you're talking about an actual "tooth" that drives the timing belt? If I read you correctly, then the cam timing would be off and there would be bigger issues than what was stated.

Fireproof13 · 04-16-2018, 02:18 PM

Quote:

Originally Posted by Charlie-III

Thanks for closing this out.
Glad it's fixed.

How the FRIG did a tooth get broken off?
Was a timing belt done recently?
Was this vehicle in a front end collision at some point?
Do you have steel eating rodents by your house?

It happened at some point during the rebuild we did. The rebuild went seemingly well, but then we started having these issues when it was done. My dad guesses that he must have either dropped it or bumped it with something since he did that part. Those teeth are pretty small and appear to be fairly brittle so even a dropped socket could probably break one.

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03-26-2018, 09:00 PM	#2
HudsonBrown1 Scooby Newbie Member#: 483870 Join Date: Mar 2018	Im assuming that it is an etb (Electronic Throttle Body) if so it sounds like the motor is gone bad and its just going haywire, I would just replace the entire assembly you can probably get a used one off eBay fairly cheap.

03-27-2018, 09:09 AM	#3
Fireproof13 Scooby Newbie Member#: 321863 Join Date: May 2012	Unfortunately that is the replacement throttle body doing the exact same thing. We finally decided to let the dealership take a look at it and it seems that we may have found the problem. The crankshaft pos sensor should sense 30 teeth on the crankshaft sprocket and it is only sensing 29. We don't know why it isn't sensing one of the teeth, but I ordered a new sprocket and I'm gonna start with that. The mechanic explained to me that all of our symptoms make sense for this issue, so it seems that we at least have a lead on the problem. I'll update when it's fixed. I was a bit skeptical that the sound that the throttle body is making could be related to a crank pos sensor issue, but the mechanic assured me that it is part of a self diagnostic that the computer runs through after clearing a crankshaft related code.

03-30-2018, 02:27 AM	#4
CosmoTheCat Scooby Newbie Member#: 3409 Join Date: Jan 2001 Chapter/Region: NWIC Location: Oly Vehicle: 98 My FMIC Is bigger than yours.	The ECU runs a throttle body sweep after you shut the key off. When you clear the memory, you erase the learned stops and it has to redo the sweep before it will allow the engine to start.

04-06-2018, 04:20 PM	#5
Fireproof13 Scooby Newbie Member#: 321863 Join Date: May 2012	The issue has finally been resolved! Turns out that the crankshaft sprocket had a broken tooth. I put on a new sprocket and it's good to go!

04-07-2018, 02:28 PM	#8
IanT-EJ22 Scooby Newbie Member#: 477892 Join Date: Nov 2017 Chapter/Region: NESIC Location: Waterbury Center, Vermont Vehicle: 2000 Impreza Wagon Silver	Thats crazy. I don't have alot of experience owning cars with ETBs but it does make sense that the ecu would have some self diagnostics and fail-safes built in.