ABS constantly pulsing until ABS light on

EvilAsPie

EvilAsPie

New member
as the title says it appears my abs is kicking on all the time. At higher speeds is harder to feel, but still there. And at slower speeds it very noticeable, inski felt it the other day. The brakes almost feel like they are pulsing rather then normal abs, but i can hear the abs pump.

I just put on new pads and rotors. left on stock lines and fluid. Gave them a quick bleed. Once this started happening i went back and tested that all pads and calipers slide well and cleaned both rear abs sensors and rings. But it looked like i couldn't get to the front ones. I have an 03 wrx. Are the front abs sensors and rings inside the knuckle on those or is there a trick to getting to them?

is there anything else i can do to try to fix this? Will autozone's reader be able to read abs codes or do i have to bring it to subaru to have them use their special one?

for now i have pulled the abs fuse and the brakes seam to work fine.

any advice would be priceless.

 
I sent it to him. On my 98 legacy GT you can pull the error code by using a diagnostic plug. Hopefully it will work for him

 
...the rest of us demand TRANSPARENCY here!

fork over the info or /thread

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or just a synoipsis would be OK, too..."ABS'll flash and pulsate when you gots schmutz in the wheel sensors" etc etc

 
This reminds me of what happened to my 02 WRX, when it was nearly new I had ABS problems. Every time I went over thirty mph and almost anytime I braked after that regardless of speed the ABS would kick in a tiny bit.

The dealer at the time (MMM) put in a whole new ABS module and things were good after that. I will look for bulletins regarding this issue. I dont recall ever seeing any but I do recall this being a problem for some people on the forums with 02-03s near the begining on the US wrx era. And I remember reading a Baja owner in PA going to court because of a similar issue.

 
If your ABS light is on the ABS computer will store an error code, much like the ECU. You can read what each code is with a simple procedure. Here it is (98 legacy GT wagon)

Under the dash, above and to the left of the gas pedal there is a large bundle of wires. Remove the plastic panel below the steering column to make finding it easier. Look carefully, there should be a small (1/2 inch), BLACK plug hanging down from that bundle. On mine the plug was taped to the bundle, look carefully, it took me 1/2 hour just to find mine because I didn't know exactly what I was looking for. The documents I read said the plug is green, on my car it is in fact black. There are wires with two small metal prongs taped to the wire connecting to the plug. The prongs may be taped up and not visible (as was in my case) or may be hanging next to the plug already, expose the two prongs.

Looking at the black diagnostic plug, it has two holes on top and four on the bottom, like so:

____X X

__X X X 6

The X's are the holes you don't care about and the six being the hole you do care

about. With the key in the OFF position, plug one of the metal prongs into position 6, the bottom right one as you are looking at the plug.

Turn the key to the "ON" position, and observe the ABS light. It should start flashing at you, a long flash is for the tens value, the short flash for the ones value. It will always flash code "11" as the default code regardless if there is a problem or not (one long flash followed by one short one) In my case it flashed code 11 and code 21 (two long flashes and one short one) with a short pause between each code. the codes repeat for five minutes so just take your time and count the flashes several times to confirm you have the correct code.

Trouble code list:

Code Indicates

None: Problem in light drive circuit. Light has to come on for 1.5

secs after ignition is on.

Light On: Same as above

11: Start Code

21 FR wheel sensor open circuit or input voltage too high

23 FL

25 RR

27 RL

22 FR wheel sensor when no open circuit or speed signal input

24 FL

26 RR

28 RL

29 Faulty tone wheel

31 FR Faulty solenoid valve circuit in hydraulic unit

33 FL

39 Rear wheels

41 Faulty ABS control module

42 Source voltage is low

51 Faulty valve relay

52 Faulty Hydraulic Motor and or motor relay

54 Faulty Stop Light circuit

56 Wrong control module used or faulty G Sensor

In my case, I looked at the wheel sensor and the connecting wire for damage. There was none so I traced it to inside the engine compartment to find it....unplugged!!.
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In my case I reconnected the plugs for the wheel sensor and the code went away. If the code does not go away, take the prong that is sticking into the diagnostic plug and remove it and plug it back in three times in quick succession. That supposedly clears the code. The computer only stores three codes at a time so make sure that when you are done you only get code 11.

Enjoy saving yourself a trip to the dealer
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Here are some web pages that I found to be useful and good for further info:

http://www.carkb.com/Uwe/Forum.aspx/sub ... -95-legacy

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

Disclaimer: I am not 100% positive that this is the correct procedure for your model Subaru. If you F%^ up your ABS system, don't blame me.

-----Added 10/8/2009 at 07:42:51-----

There ya go Nigel

 
Edit, i was describing the airbag diagnotic connector sorry, removed.

But there are no codes on Peter's car. No ABS light on. It just buzzes the the system when braking. Buzz, roll ,buzz, roll, buzz, roll, then stop. Odd. I have a feeling one of the speed sensors is reading, then isn't, then is, then isn't. Like it thinks its working right, like its suppose to, but its def not right.

 
Last edited by a moderator:
Edit, i was describing the airbag diagnotic connector sorry, removed.
But there are no codes on Peter's car. No ABS light on. It just buzzes the the system when braking. Buzz, roll ,buzz, roll, buzz, roll, then stop. Odd. I have a feeling one of the speed sensors is reading, then isn't, then is, then isn't. Like it thinks its working right, like its suppose to, but its def not right.
Click to expand...
well that light does come on, but only after about 5min of driving, in which time the abs is kicking on whenever braking. Then once the light comes on no more problem. I guess i forgot to re-write that part after the title.

So i guess once the light is on the abs is disabled or something. Either way i have pulled the fuse so i can at least drive normally. Is that bad to do for a long period of time? I'll get around to putted the fuse back in, going for a drive, then checking codes hopefully this weekend.

Thanks all!

 
i think i just read somewhere about a bulliten from subaru saying that the rear sensors had somekind of problem in the harness. it may only pertain to 02 model not sure but google tsb for 03 and 02 wrx. sometime if it is early model 03 or late 02 it can have some of the problems of that year.

 
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