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ABS question

Posted: Fri Oct 28, 2016 9:33 pm
by LegacyLover
I need some advice about my ABS system.
I haven't been able to find an answer on the internet thus far, and even my mechanically savvy friends are at a loss.

My ABS light is on. Most of the time when I start my car, it is off, but as soon as I go over a bump or hit a pot hole, it will come on. When it does come on, I often hear a faint hissing noise, and then when I go to apply my breaks...it sounds like my car is making a terrible farting noise. The farting noise only happens when the hissing is present. This happens especially on colder mornings, but it has gotten to the point where it might happen anytime. The brake pedal feels a little weird and vibrating when the noises happen, but it feels like it still engages, and it stops fine, it just makes the terrible noise.

I did take it into the Subaru dealership to have it checked out once, about a year ago (because this has been happening for a long time and I kept ignoring it) but of course it didn't make the noise for them, just the ABS light on, and they said that their equipment was not able to communicate with the car to figure out why the ABS light was on and that it would require a significantly further investigation into the cause.

Any thoughts on what might be going on? I really appreciate any input.
Thanks!

Re: ABS question

Posted: Sat Oct 29, 2016 12:19 am
by Pntaste4evr99
When I broke my rear ABS sensor it did the same thing, vibrating peddle, light on ext. I found u can look at the flashing light on the abs module itself and it will tell u (kinda) what's wrong. Mine blinked Lt rear sensor, replaced sensor with used ones (3 times) and light still come on, and peddle feels weird at first, and light will come and go as it pleases. So really I'm no help to u, just saying I have kinda the same problem. Lol

Re: ABS question

Posted: Sat Oct 29, 2016 4:58 am
by Legacy777
Welcome to the BBS.

What year and model Legacy do you have?

If it's a 90-94 take a look at this scan.

https://main.experiencetherave.com/suba ... bsdiag.jpg

The ABS computer is under the front passenger seat and there is a little flap in the carpet to lift up so you can see the flashing light.

Re: ABS question

Posted: Sat Oct 29, 2016 5:57 pm
by Pntaste4evr99
Josh, is there a way to "reset" the module after you've replaced what it was blinking what was wrong?
Mine has blinked saying Lt rear wheel sensor, I've replaced it 3 times now with junk yard ones (which is possible I guess to get 3 bad ones in a row, but not probable) I have access to the FSM and I've never found anything about a reset, just drive and it will take care of its self.

Sorry I don't mean to hijack someone else's post......

Re: ABS question

Posted: Sat Oct 29, 2016 6:22 pm
by rallyak
It reset it self every time you turn the car off. Are you using first gen sensors or second gen sensors? Are the used ones that you replaced where they rusted in? I found that the rust will crush the sensor and short it out internally, that's why I've been using second gen sensors because they are plastic and work just fine.

Re: ABS question

Posted: Sat Oct 29, 2016 7:38 pm
by Pntaste4evr99
All of them have been the plastic second gen ones.

Re: ABS question

Posted: Sun Oct 30, 2016 6:22 pm
by Alphius
You probably have a wiring issue instead, the ABS ECU is reset and self checks on every key cycle.

Re: ABS question

Posted: Sun Oct 30, 2016 7:15 pm
by LegacyLover
Thank you guys! I appreciate the advice! I finally have a chance today to check out the ABS computer, and I hope that gives that answers I need.

Re: ABS question

Posted: Sun Oct 30, 2016 11:41 pm
by Legacy777
Keep us posted what you find out.

Re: ABS question

Posted: Thu Jan 19, 2017 5:00 am
by CAV3MAN227
-I have the same issue. My abs light turns on sometimes, usually during a left hand turn, hitting regular bumps in the road. I'll have to check it out now based on the info given here. I'll keep an eye on this post.

-Joe