ABS pump motor running non-stop....

[soobcollektor]

My mom called me today all frantic to tell me that there is a motor humming sound comming from under her hood whether the car is running or not (95 Legacy L Sedan AWD 173,000) Well trying to explain to her what to do over the phone didnt work, so 2 hours later I get there to look at it myself, The ABS motor is running non stop, doesnt matter whether the key is on or off.....what gives?

 

The brakes still function completely normal and the ABS light is on, what in the world is causing this, I pulled the fusable link under the hood to shut the motor off, It was the red on in the front of the box and the ABS motor shut off. It was a little warm after running for 2 hours, but i'm completely stumped, I thought most everything got its power shut off when the key is switched off so what in the world would cause the ABS pump motor to run like that?

 

Confused as hell,

Tim

[nipper]

The abs i think will run with the key off under the thoery that if you stall and have to roll to the side of the raod, you still have brakes, and aneed for abs, though i am not 100% sure on that, im sure somone will correct me.

There is a fuse for the ABS, that i thnk is only for the abs. You can pull that fuse.

The ABS puter i think turns the pump on by completing the ground.

This setup rarely blows a fuse when blown when there is a short, thats the down side to it.

The way the abs unit itself works that once the abs is told to activate, the first solenoid activates to cut off the pressure from the master cylinder (meaning the driver cant apply more pressure to the brakes, but can relase the brakes and the fluid will be released) The Motor then turns on at the same time

http://www.dashdriving.com/tutorials/abs.htm

 

The motor is there to help modulate pressure in the braking sysytem.

From what i read, the motor is either grounded out, or there is a problem with the abs brain. The ABS light is telling you there is a failure. SInce this is an odd ball failure, i would say get it loked at as i cant tell you how this fault is interacting with the rest of the system. Normally i would say it wouldnt have any effect on braking. But if this unit is chewing itself up or something, i wouldnt want the responsablity or guilt of being wrong.

Have it checked.

 

nipper

 

PS

 

another good ABS explination, bnut not relevant to your problem... no such thing as too much information

http://www.geocities.com/nosro/abs_faq/

[sea#3]

The ABS motor relay is sticking on, it is located under the black cover that says "ABS " on top of the Hydraulic unit ,just remove the screw in the centre of the cover. There are 2 relays , the one closest to the front of the car is the one .You can get the part# off the relay

 

Hope this helps

SEA#3

[nipper]

The ABS motor relay is sticking on, it is located under the black cover that says "ABS " on top of the Hydraulic unit ,just remove the screw in the centre of the cover. There are 2 relays , the one closest to the front of the car is the one .You can get the part# off the relay

 

Hope this helps

SEA#3

 

 

way cool. Since you seem to know more about the "nuts and bolts" then i do, what does the motor do, does it pump the pressure, or activate the the modulation some how. Yes i would love to take one of these things apart

 

 

nipper

[soobcollektor]

Interesting, I will take a look at that pump unit itself tomorrow and see about that relay, as for now she is driving it with the fusable link out so it wont run.....I'll post back what i find...

 

Thanks

[OB99W]

Reference info:

http://endwrench.com/images/pdfs/IdentifyInfo.pdf

http://endwrench.com/images/pdfs/ABS.pdf

[nipper]

Reference info:

http://endwrench.com/images/pdfs/IdentifyInfo.pdf

 

cool, thats getting saved

 

 

nipper