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Here's the deal. When braking from lets say 50 mph to 0. A time or two while slowing down it will "coast" a bit like ABS is kicking in.

 

No ABS light, pulled ABS fuse and problem went away (and ABS light came on).

 

RR caliper was hanging up. Replaced that and issue still persists.

 

Best way to check this since no ABS light is on?

 

I'm in the rust belt so tone rings aren't looking that good - but on other cars where they were bad the ABS light is on.

 

Suggestion? Threads?

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Here's the deal. When braking from lets say 50 mph to 0. A time or two while slowing down it will "coast" a bit like ABS is kicking in.

 

No ABS light, pulled ABS fuse and problem went away (and ABS light came on).

 

RR caliper was hanging up. Replaced that and issue still persists.

 

Best way to check this since no ABS light is on?

 

I'm in the rust belt so tone rings aren't looking that good - but on other cars where they were bad the ABS light is on.

 

Suggestion? Threads?

 

Does the pedal vibrate like the ABS is kicking on when this happens?

 

If you unplug a wheel sensor I wonder if the rest of the system will still function? If so you could disconnect them one at a time in sequence and when the problem stops, it's that wheel.

 

 

Dave

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I've been off searching. Haven't found this exact problem but a the end of this I'll tell what I've found so far.

 

The pedal doesn't seem to do anything - perhaps get temporarily "mushy". No pulsing is heard - or really felt for that matter - the car jsut "coasts" for a little bit then starts braking again.

 

No ABS light at all. Before, during, after. But it just "acts" like ABS.

 

WIth the fuse unplugged the issue doesn't happen.

 

 

I found some hits for "ABS code"

 

Bleed brakes(all 4 in specific sequence).

 

Find BLACK 6 pin connector under dash to the right of steering column along with 2 grounding pins.

 

 

Read codes and look them up. (Pray it isn't tone rings).

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He gets 11(naturally)

46

42

51

 

I'm off to try and hunt them down now.

 

Too bad it's not like ODBII codes and there is a master list.

 

I found some links to some PDF's so I'm looking through them.

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I don't have a listing for ''46''. ''51'' is defined as ''Abnormal valve relay''. However, ''42'' is ''Source voltage is abnormal'', and that should probably be dealt with first. It could signify a battery/alternator problem, a connection/wiring problem, or possibly just that a fuse was pulled. First, check the battery voltage, and if it isn't normal do what's necessary to take care of that. Next, I'd suggest starting with clearing the ABS memory so that the codes can be checked again.

 

To clear the ABS memory, connect a ground probe to B82 pin 6, and turn the ignition switch ''ON'' (don't start the engine). You should get the codes, as before. Then pull the probe from pin 6 and quickly reinsert it three times (you have to complete that within 12 seconds or so), leaving it in pin 6 the last time. You should then hear the ABS unit sequence (expected when codes are cleared) -- allow it to complete the cycle. After turning the ignition ''OFF'' and then ''ON'' once more (again, not starting the engine), the ABS codes can be read. At that point, you might just get the ''11'' code, or more.

 

Recheck codes after another drive, and post what shows up then.

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I'll recheck tomorrow.

 

His snap-on scanner said something aboug a G something (G- relay?) under the console somewhere. I recall reading something about it - I think in a PDF someone posted about WRX ABS issues, or in another thread. I'll have to refind the info and read it closely now.

 

When I've had tone rings (about the worst thing to fix - I don't) the ABS light comes on. The ABS light does work, but isn't on.

 

 

He has already swapped another relay under the dash from a 97 Outback parts car that I have to try and fix the code 51 I believe. That's the last time we had talked.

 

At one point we had pulled the ABS fuse today to confirm that it was something with ABS. So the first time he got the codes one of them could have been the pulled fuse.

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His snap-on scanner said something aboug a G something (G- relay?) [...]

The ''46'' code you previously mentioned was likely misread, and is probably ''56''. ''56'' is ''Abnormal G sensor output voltage'' -- that's ''G'' as in ''gravity forces''. The code doesn't necessarily indicate that the sensor itself is bad -- it could be a connector/wiring issue.

 

 

He has already swapped another relay under the dash from a 97 Outback parts car that I have to try and fix the code 51 I believe. That's the last time we had talked.

The ABS valve relay is inside the ABS control module.

 

While it's certainly possible to have two separate ABS problems, you should still verify that the battery voltage isn't low, since that can sometimes cause the control unit to misbehave.

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  • 2 weeks later...

No ABS light but typically twice at different speed slowing from 55 to 0 ABS kicks in for a few pulses.

 

All sensors read some AC current when spinning by hand. G-force thing in console swapped out with no improvement.

 

Pull ABS fuse ABS light comes on. No ABS but stops just fine.

 

Tone rings especially on the front look bad but usually this triggers the light.

 

This will be a low dollar car (121k and will sell for under 2k I believe). So I don't wanna spend forever chasing the porblem and I have a 97 OBW to steal parts from.

 

What's next - ABS unit and how much of a b$itch to bleed.

 

Take it to the dealer (and add significantly to the selling price).

 

Pull the fuse and have no ABS?

 

If I find the connectors under the dash will they flash anything if no ABS light is on? It's certainly had enough cycles to turn the ABS light on if something is truely wrong.

 

He says no new codes (just had the battery disconnected to swap the G-force sensor). He'll recheck for codes this morning and then I'll research and post any if htere are any.

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Didn't someone just link to an article on a tone ring that looked good but had been repaired, or some such, and it was causing the ABS to go on?

 

They looked at the signal with an oscilloscope.

 

 

Dave

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Now that would be way, way over my head.

 

Essentially, every time a block on the tone ring goes past the sensor, it generates a pulse. If the tone ring is damaged, and the pulse is too small or is not there, the ABS computer thinks that wheel has locked up.

 

Not for a subaru, but relevant:

http://www.brakeandfrontend.com/Article/38809/Replacing_.aspx

 

"A difference of only a few thousandths of an inch in the height of the teeth on the tone ring can affect the WSS signal."

 

"Magnetic sensors can also pickup metallic wear debris from the rotors and pads, causing the sensors to read erratically and confuse the anti-lock brake system. Cleaning the sensors and resetting the air gap can often restore normal operation. But if the tone ring is corroded or damaged, it must be replaced."

 

"In the case of the Chevy/GMC recalls, road salt was apparently working its way into the hub assembly at the sensor hole and attacking the tone ring. In many instances, the problem was not bad enough to set a fault code and turn on the ABS warning light. But it was bad enough to generate misleading wheel speed readings and trick the ABS system into kicking in and pulsing the brakes when ABS was not needed. The problem typically occurs at speeds under 10 mph, and greater than 4 mph."

 

Dave

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As has already been suggested, damaged tone rings could be the problem. So could a corroded tip on a wheel sensor, or even excessive hub runout.

 

I've mentioned this before, but haven't seen a response indicating it was checked, so ... Have you verified that the battery voltage is okay, and ground connection is solid? ABS electronics can malfunction if the supply voltage is too low, sometimes indicating multiple faults. If the voltage is adequate, then the problem is more likely at a wheel.

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  • 5 months later...

Sorry to resurrect an older thread. I just did some searching and it wasn't quick to be found. And my memory is failing me, it's cold outside, I was in bed w/sinus "issues" and I'd have to look for a flashlight and head outside tonight. Hoping that someone knows this to put my mind at ease until I get out there in the morning.

 

Someone just called to test drive this car tomorrow morning knowing it has the ABS problem. But I still want to pull the fuse and I forget where it is. Is it in the main fuse panel under the dash or on the drivers fender well?

 

I gotta pull the fuse, find the pass side timing belt cover I removed to see if the belt looked like it had been replaced and re-install it, and take it around the block to clean up the brakes by 10am.

 

And meet a realtor to get into the hosue that I bought today. First real cold morning here this year and I expect to be moving slowly...

 

Any thoughts appreciated (mostly for peace of mind). In the morning hopefully I can figure it out/remember where it is myself.

 

Thanks.

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Perhaps this is an apples to oranges comparison, but I once had a BMW with badly rusted tone rings. It would pulse the ABS at slower speeds on braking, but would only set the ABS warning light if you exceeded 80 MPH!

 

I'd say to start with the known bad parts (tone rings) and work from there if you still intend to attempt to fix this.

 

Nathan

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