Abs Problem

[James Matteu]

I searched the code you mentioned "high pressure..." :

 

"may indicate a failure to build up pressure because the fluid level is low or there is air in the system. There's a special "maintenance bleeder valve" under a red cap on the modulator that must be opened to relieve pressure inside the modulator any time the modulator, pump or accumulator is serviced. Honda has a special T-handle wrench (07HAA-SG00100) that can be used for this purpose. To relieve pressure, turn the bleeder screw one complete turn (key off), then stop. Wait until the pressure is relieved, then close the screw."

 

this might help?

That is another Honda system (non-5G Accord) you are referring to. The 1996-1997 ABS systems do not have a maintenance bleeder valve that is seperate from the ABS Unit. I worked on a 1991 Acura Integra GS, and it had the exact system you are referring to. Instead of having extra plumbing and a relief valve, 1996-1997 Accords have an internal pressure relief system, a gas charged accumulator, and an ABS Unit mounted bleed bolt. The accumulator's N₂ chamber reduces the brake fluid's discharge pressure, otherwise any bleeding operation would release a high pressure stream, hense the special tool you referred to (Honda T/N 07HAA-SG0-0100). On our ABS Units; a rubber hose, waste bottle, and 10mm open-ended wrench suffices. Infact, I bled mine the other weekend with an empty 20 oz. water bottle and some spare fuel line.

[James Matteu]

Where exactly is that sensor at?

The diagrams show the sensor behind a plate held on by phillips screws. The plate seems to be on the backside of the unit, i.e. it looks like you would have to remove the unit to get to it.

 

Would bleeding help my situation or no?

I don't think bleeding would help since bleeding remedies aerated fluid, where aerated fluid is more compressable than non-aerated fluid and cannot achieve the necessary pressure to operate the system, i.e. low pressure/motor over-run Code 1-0, like me.

[James Matteu]

Still haven't gotten around to bleeding the thing since the reservoir has surface cracks and is chipping away. I assume this is from repeated exposure to brake fluid and conditions under the hood. So I am replacing the reservoir first, then bleeding.

 

I got it last weekend, see my new goodie!

 

Honda P/N 57019-ST5-000:

 

[James Matteu]

More goodies, since my reservoir didn't have a label:

 

 

 

Honda P/N: 57119-SN7-003 seems to be for an international market since there is no lettering on it to indicate ABS, just the funky lookin stop-sign.

 

[James Matteu]

Okay this is were I left off.

 

Code 4-1: Description: Wheel Sensor, Right-front

 

Reason: Funny story, I was doing a brake job and left one of the bolts behind the hub loose. A few days later it finally worked itself loose and fell out. Just not before it could lodge itself between the wheel sensor and the CV Axle. The bolt ground the gear pulser smooth.

 

Code 1-0: Description: ABS pump motor over-run

 

Probable Causes:

1. Air mixed in the ABS brake fluid

2. Pressure switch stuck OFF

3. Open circuit between the pressure switch and ABS control unit

4. Open circuit in the P-SW circuit between the pressure switch and body ground, or a poor ground

5. Drop in pump discharge volume

6. Leaking outlet valve

7. Leaking relief valve

8. ABS brake flluid leakage

9. Faulty ABS control unit

 

I am going to reperform the bleeding procedure next payday. Again, any ideas, feel free to contribute.

 

I am thinking I have some kind of slow leak and/or air in the pump. I will re-bleed and pressure wash the engine bay. This way I will be able to spot any new leaks, versus any slow weeping seals.

I know, I know, that was February, now it is September. I have been lazy and after pulling the ABS relay, the pump doesn't run and I have no noise to bother me; out of sight (or sound), out of mind, yeah yeah, I know.

 

So I checked the level again today and it hasn't changed since January which is when this started, i.e. no leaks. I bled the system after replacing the Honda P/N 57019-ST5-000 (the reservior), and still the pump comes out with code 1-0 ABS pump motor over-run.

 

At this point I am confident that the Accumulator is not leaking, as there would have been a change in fluid volume. I am now convinced, but not certain, the problem is the high pressure shut-off. The only thing is, I don't get any high pressure codes, only over-run codes.

 

Well, it may just be time to replace the entire thing.

 

Let me know what you guys think.

[James Matteu]

bump.

 

I am thinking that the accumulator may be faulty based on the number of internet sources saying pump over-run is caused by faulty accumulators. These sites constanly refer to a leaking accumulator, but I have no visible leakage.

[LndRvrUS]

James, how difficult was it to replace the reservoir? I too have been having an ABS light issue on my 96 Accord EX 4-cyl and finally decided to look into the issue when I thought I was starting to get a noise from my right rear wheel. Turns out the noise is the need for a new set of pads but I've decided to dive into the ABS issue now. I'm looking at ordering a new reservoir from Magestic and hope that will solve my problem since it's starting to chip pieces off. I also thought about replacing the o-ring on the accumulator because that's a known issue on my 01 DiscoII. It appears that replacing the reservoir tank is pretty straight forward and based on your pics, the new one came with the o-rings included. Any additional issues I should keep an eye out for?

 

Thanks.

[James Matteu]

The reservior is very simple, just remember to slap the end of the screw driver before turning (old skool impact driver) or you may strip the screws.

 

Have some kind of high pressure washer handy to clean any spilt brake fluid right away or kiss your paint good-bye.

 

As far as the over-run...

 

Update: the over-run is now improved!

 

The pump doesn't always generate an over-run error, but does cycle several times to build pressure. I am thinking of: 1) bleeding the system again, 2) taking it to Honda so that they can bleed the system while cycling the solenoids to ensure any trapped air is released, or 3) doing both in the order I have listed.

 

Sometimes the pump still over-runs causing the ABS control module to open the fail-safe relay, taking the ABS system off-line.

 

I am going to keep looking for any sign of an external leak and cross my fingers that I do not have a leaky solenoid.

 

LndRvrUS, keep us up-to-date and let us know if the Accumulator solves your problem. I have read countless threads where the OP claims a faulty accumulator was the source of their problems. I noticed that most of these OPs describe an external leak in conjunction with the over-run error. I know that a new Accumulator comes with a new O-Ring and therefore remain unconvinced that everyone that replaces their Accumulator needs a new Accumulator; I think those people with fluid leaking to the exterior of the pump may only need a new O-Ring.

 

I digress, LndRvrUS, keep us up-to-date, thanks!

[James Matteu]

Update!

 

I bled and re-bled the system. The constant re-bleeding flushed out any old fluid; since I kept replacing the fluid rather than recycling what came out: I used about one bottle of Honda Brake Fluid.

 

I have finally come to a conclusion on this matter, I have an internal leak. I think the leak is in the pump since the ABS computer is not throwing any high-pressure error codes.

 

What I observe:

The motor runs, depleting a small volume of fluid from the reservoir, then stops. This indicates the system is able to reach the required internal pressure.

 

After the motor stops, I observed the brake fluid flow back into the reservoir. After the level rises about a quarter inch, the pump starts up again.

 

This cycle continues until the over-run error is triggered, shutting off the ABS system and storing an error code in the computer.

 

I reviewed the pressure schematic for the ABS system and see that every part of the ABS system is able to overflow back in the reservoir. The solenoids, the pump, the relief valve; any or all of these could have the small leak that is causing the fluid to flow back into the reservoir.

 

If anyone would like to contribute, I would appreciate it.

[James Matteu]

Update!

 

I tried replacing my ABS Modulator with a Nissin ALB3 unit from a low-milage 1997 Acura TL 2.5 Premium since they seem to have the same Nissin ALB3 unit found in 1994-97 Honda Accords and 1993-97 Acura Integras.

 

Well, the pump solenoids consistently failed to activate on start-up. It may have been a problem with the High-pressure switch, but manually running the pump also failed to reduce the volume in the Accumulator which leads me to believe that the Accumulator passage was damaged or that the High-pressure switch was blocking flow. Either way, the pump seemed to constantly cavitate rather than catching prime.

 

The unit came with a one-year no-questions-asked warranty, so I can return it for another unit or credit. Funny story: I bought the ABS Modulator for $78. The salvage yard owner claims there was a mistake in their computers, the price should have been $780 dollars, not $78. He said they would be changing it right away, but not before I was able to buy mine with a one-year warranty.

 

Anyway, so I put my pump back in and flushed the unit with new fluid. I start the car up and got no over-run! I noticed the fluid coming out looked funny: it was rose colored. Almost like faded ATF fluid. I will see how long this lasts, but now my dash looks wierd with no ABS light illuminated.

[Bravesball20]

Ive notice that my honda leaks under the abs too, and i have the same problem with it when it starts. I have a 95 accord ex v6

[James Matteu]

UNBELIEVABLE! I cannot believe I've been dealing with this problem since 2008!!!!

 

 

Just yesterday I replaced the modulator with another unit (this makes unit #3) and it worked flawlessly. Back in 2009 when I swapped in the TL Nissin ALB-3 the motor never ran and solenoids wouldn't cycle. In hindsight, I didn't bench bleed the unit prior to running the solenoids which would have alot to do with why it failed to work. That TL unit is moot anyways, I figured it was FUBAR and dismantled it to try and learn more about how the unit works. Based on my observations, and the "autopsy", I hypothesized that old o-rings at the High Pressure Relief Valve caused the failure in my OE modulator.

 

Yesterday, I found this hypothesis to be incorrect. The 3rd unit did the same thing the 1st did: the pump would run, then fluid would flow back into the reservoir from the suction line to the pump, then the pump would run again. In the first unit, this would continue until the ABS-Control Unit would open the Fail Safe Relay to de-energize the system and store the Over-run Error code with the ABS Malfunction Indicator Light illuminated. The difference yesterday with the 3rd unit was that after some more bleeding the pump stopped cycling like that and no more fluid backflowed into the reservoir. What proved my hypothesis wrong was that I believed what I was seeing was fluid flow from the High Pressure Relief Valve into the reservoir, in actuallity I was watching fluid flow back from the pump suction line. I know this cause the previous owner used blue DOT4 brake fluid, and I use amber Honda DOT3. I told myself I didn't see blue in the reservoir when I was sure the High Pressure Relief Valve was opening because I had flushed the blue stuff from the modulator. When I was done bleeding and priming the ABS Modulator, the High Pressure Relief Valve finally did open (for the first time) as I observed a spot of blue appear in the reservoir that had not appeared before. That's when I realized where the fluid back-flows were coming from: the pump. There's only three places brake fluid can possibly enter the reservoir: the filler cap, pump line, High Pressure Relief Valve. I wasn't using blue DOT4, so it wasn't the cap.

 

So, now I have the 1st unit off the car, the 3rd unit working beautifully, the 2nd unit in pieces, and I'm ready to remove the pump from the 1st to figure out how exactly it failed and how I can fix it.

 

BTW, I retested the 2nd unit's pump/motor and it works fine. I'm thinking after I figure out what happened I can use that motor/pump to refurbish the 1st unit should the 3rd fail at some point in the future.