club.liberty.asn.au

Hi

I have a MY09 Liberty 2.5i manual sedan, 70,000kms. All is fine except recently I started to get a "toot" noise, a bit like a very quiet horn going off for a fraction of a second when I take off. Happens most of the time, sometimes not when cold.

I thought for a while it was the DMF squeaking but I discovered if you just leave the car in neutral and give the accelerator a small/brief tap, you can hear the toot/squeak. I recently had a service and my independent mechanic confirmed it was coming from the front passenger side, down near the firewall somewhere. He suggested a noisy ECU (I have no idea how a PCB can generate such noise).

I'd really like to get to the root cause, it's very annoying. Can anybody shed any light on this?

thanks

(1) an MY2009 Manual 2.5i will not have a DMF
It will be a Flex-Flywheel.

(2) check that the sound is not from the electronic throttle control for the DBW system

(3) sounds within the cabin bounce around all over the place and can be hard to pinpoint.
Example, one time Mrs Wife was driving her Forester and asked me to fix the rattle coming from my side of teh cabin.
I said that it was coming from her side, sure of it.
Turned out to be her sunglasses in the overhead bin near the rear view mirror.

BillyCorgi wrote:(2) check that the sound is not from the electronic throttle control for the DBW system

Thanks for the info, sorry thought it was a DMF. I'm not very intimate with Subarus. Can you elaborate a bit more..does the DBW have its own ECU? Where can I find the schematics for the electronics/DBW setup? Apologies if these are basic questions.

I'd say the sound is normal and is likely the DBW system.
No it won't have a separate ECU for that.

If you get in another gen 4 2.5i I'm sure you'd hear the same noise.

Surge wrote:I'd say the sound is normal and is likely the DBW system.
No it won't have a separate ECU for that.

If you get in another gen 4 2.5i I'm sure you'd hear the same noise.

I see thanks. I don't believe it's normal. I used to have another gen 4, never heard it. Also I've had this car since new and it has never had this noise until recently. It's a pretty obvious noise. The mechanic heard it the first time he took off for a test drive and said it's not right.

My 30RB does it, passenger footwell.

From the frequency of the noise, I'd say mine is DBW. It comes and goes but seems more obvious in cold weather.

I wouldn't call it normal either as I have never heard it from any other car, not from inside the cabin. It is however, normal for the throttle motor to squeal when it's powered.

Did you end up finding a fix? My 08 2.5 is doing the same thing and it is driving me up the wall.

The ECU is just under the passenger carpet (in the footwear under a plate). Just removing a few trim pieces and lifting up the carpet will confirm if the noise is coming from there if it gets louder with those removed.
But it's still an odd sound to suspect an ECU to do...

If you're really keen and have a spare $69, buy a Noise Detection kit like this one:

http://www.ebay.com.au/itm/172306601771

I got one and it's brilliant!! Like BillyCorgi said, sounds bounce around. With the directional microphone and headphones in the kit, I traced an 'interior' rattle to a rock in the driver's side side skirt. I would've never found it without it. It also has clamps that can attach to various eg engine bay components. And you can switch between the different inputs to narrow down on areas that are closer to the noise.