mherrcat

...comes on intermittently. Code shows 18 (High Pressure System?). How do I fix this?

Brownjd

from what i was told u have to replace the abs unit (extremely expensive)... i just took the abs relay out and live with the light on. but if anyone has any ideas to get the light out, id like to know!

HonBeer

The accumulator o-ring is most likely leaking.Its a $2.00 part. You need to remove the modulator assembly to get to the bolts to replace the o-ring on the accumulator.

mherrcat

I have read about the O-ring fix. Does it require removing all the brake lines to the unit? I assume it will require bleeding the unit.

HonBeer

It does require removal of the ABS unit. There is no way of getting round that. Goodluck. CHEERS!

phootbag

No to all. The possibilities for this DTC are a wiring problem, a leaking solenoid valve in the modulator or a malfunctioning ABS accumulator. Low fluid level usually will not cause this DTC.

It has been my experience that a faulty ABS accumulator is the most common fault. I have watched technicians replace the entire modulator assembly ( with accumulator ) and act proud because the vehicle was fixed. This is unfortunate because the accumulator is far less expensive than an entire modulator assembly.

The fault of the accumulator isn't typically gas leakage. The problem has something to do with a switching mechanism within the accumulator.

My advice is to replace the accumulator and recheck.

P.S. Removal of the modulator assembly is not required to replace the accumulator. BLEED THE ACCUMULATOR FIRST !! Unbolt the modulator from the body of the vehicle, lift the modulator an inch or two, support it with a block of sorts and use a wrench to remove the two bolts that secure the accumulator.

mherrcat

Thanks phootbag. I had read in another post that it was possible to remove the accumulator without removing the entire modulator.

There does not appear to be any brake fluid leaking from the unit.

I tried bleeding last week and didn't get any bubbles, etc., but it didn't seem to help. Maybe I'll try that again before trying to replace the accumulator.


Do you know what the torque specs are for the accumulator mounting bolts?

CRX7

By bleeding the unit you mean opening the bleed valve on top of it while someone in the car turns the ignition switch on right? This fixed it for my car, bleeding the hell out of it and replacing all the lines, calipers, m/c, fluid, helped even more. No more 15 second ABS pump runs at startup.

phootbag

By "bleeding" I mean, relieving the pressure in the accumulator by opening the bleed fitting on the top of the modulator. Key off, attach a hose to the fitting, open it and brake fluid will come out. When it stops, the accumulator pressure is relieved.

Mufasa

I don't mean to hi-jack this thread, but how would one go about checking ABS codes?

poorman212

If it is the 94 you have listed....jump the blue connector on the right/pass side-just like getting CEL codes- but your looking for ABS flashes-if any of the other (CEL, D4, ect) lights flash/blink that would be good to know as well.

HonBeer

R and R the ABS unit takes one hour at my shop. Nothing to major.

Cheers!

mherrcat

My ABS motor/pump usually runs less than 2 seconds, sometimes not all. The only time it ran longer than that was when I was bleeding it. Whether the pump runs or not, sometimes the light comes on and sometimes it doesn't. It seems like it comes on more frequently after the engine has warmed up. Doesn't usually come on when starting up stone cold.

poorman212

and WHAT CODES do you have?

HonBeer

If it runs. You have a leak. The pump running is to build pressure in the accumulator. The porpose of the accumulator is to store pressure in the event that the ABS needs to be activated. That $2.00 o-ring on the accumulator holds back 800-2000 psi of brake fluid. If the ABS pump runs constantly it is due to a leak. Is the base of the accumulator dirty/wet? That would be an indication of a leaking accumulator.

http://en.wikipedia.org/wiki/Hydraulic_accumulator

Speedx-honda

The engine should also be checked for overheating issues. An overheating engine radiator can cause the air-conditioning system's pressure to increase significantly.

mherrcat

The pump does not run constantly; it runs less than two seconds when the car is started. Are you saying that the pump should not run at all?

I understand the concept of the accumulator; boats have them (although larger and with less pressure) in the pressure water system to prevent the water pump from running constantly.

Lots of good info here and I appreciate it all! I have ordered an O-ring for the accumulator and will try that first; hopefully without having to remove the modulator entirely.

No overheating problems; radiator and all coolant, heater and AC hoses replaced last year.

poorman212

What are the codes? Yes it could be the o-ring but without knowing the codes it could be as simple as filling the abs res...

phootbag

ABS pumps that run too long usually don't set a code 18. They set an over-run code due to the modulator not being able to fill the accumulator.

redaxe

I'm very sorry to re-awaken this old post. But is there anyone who has a diagram or a good picture of a disassembled accumulator?

I got Code 18 on my stepdaughter's Honda and I would like to see what it looks like before making any unnecessary mistakes while taking it apart.

And could someone please point out to me where the bleeding valve for the accumulator is located, as I understand it's necessary to bleed it to relieve pressure.

Kind regards
Tomas

redaxe

Is there nobody who's ripped the accumulator apart and pictured the individual components?? I'm kinda desperate here and could really use your help guys. Thanks in advance!

redaxe

I found some diagrams online, but it remains to be seen how accurate they were. But I did find a website that stocks the o-ring.
57072-ST5-003 - Honda O-RING (P5) seems like a good link, but there's one drawback! They don't accept paypal payments from outside the US. A good thing one of my good friends lives in the US, so I could get him to order those pesky things for me.

Next up is to rip the damn thing apart, but for the reassembly I need the torque specs so I don't damage anything in the car. Where would I find the torque specs for the ABS system?