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Tracing faults on abs brakes isn't always easy. A Honda mechanic with an alb (anti lock brakes)tester couldn't find the fault on my honda prelude. He thought that there might be a faulty sensor. The problem: warning light comes on after driving a short distance down the road. Initially, I should explain, the warning light comes on with the ignition and goes out when the brakes are first applied. It still does this, but it comes on again only when the car is driven a short distance. I seem to remember a while ago, testing the resistances on the sensor couplings and found them all to be normal. I have'nt recently heard the alb pump working, which I remember it periodically used to. Although the car is 1986 vintage it is in good condition and it would be nice to have the alb system working properly. Any clues?
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it would be nice to have the alb system working properly.
It will be an MoT fail if it isn't!
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Sounds like you need a new ALB ECU. Hope it's separate to the pump/valve block - they used to be, though they're generally combined these days (makes them more reliable, but hellish expensive to replace).
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Mikey,
Unless Cyd has some specific model experience with this system to suspect the expensive ECU I'd hold off changing it for now.
I don't have direct experience of you car's ALB system (Honda's own or Bosch?) but applying some thought from the ones I do know...
The system ECU makes a set of tests after you turn on the ign/engine, that is when the light goes out if it is happy.
Then after a certain speed (10mph perhaps) the system looks at itself again and that is when the light comes on if it isn't happy then
Logic brings you think what is the difference between the static OK state and the rolling fault indication? Surely it has to be the wheel sensor output? They need testing for output voltage at a set test speed (spinning the wheels by hand) and the waveform quality.
Other odd things can cause this such as dirt/corrosion on the wheel sensor rotors, an odd sized tyre or worn wheel bearings. Anything that spoils a smooth even output from all four sensors.
MM
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Mikey, I agee with Middleman.
Fault will be at wheel sensor. Testing for resistance not good enough. Must have correct wave form output. Can check this first with sensitive centre reading voltmeter/milliammeter.
Really should be tested with oscilloscope so you get pictorial view of waveform.(Should be Sinewave shape but with squareish top)
Unless roadtested on MOT, this fault will not show on braketest machine.
Suggest you clean sensors and check gap between sensors and rotors for starters.
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Thanks for your replies.I agree with Lauriew and Middleman. The alb warning light only comes on again (after first being cancelled by the first application of the brake pedal),after the car has been moving a short distance, so it is logical to suppose that something's up with with a sensor output. Can sensors be cleaned? Will check the pulsers too. I don't have a 'scope, but a multimeter.I expect you could hire a 'scope. I do have the workshop manual but following the procedures isn't always plain sailing. Anyway I'll take it from here.If anything else comes to mind do let me know. Kind regards, Mike.
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How did it go with the ABS?
I've just had the same problem with my vintage 1993 Civic VTi, and am keen not to spend lots of money fixing it.
Thank you...
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I appreciate that this thread has probably gone cold now, but did either Mikey Jay or cannondale get their problem sorted. My Rover 620si 1994 has developed the same symptoms, ie ABS light goes out after start up as it is supposed to do but comes back on after travelling some 50 yards and stays on until the ignition is turned off. A Rover garage reckons to have checked out everything and say they have eliminated all but the pressure switch on the back of the pump which they recommend be replaced as it apparently can't be tested. (£170 plus vat for a new pressure switch not counting fixing charges).
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IITC the ABS units are made for Honda by a Japanese company called Nissin (not Nissan).
These units had a reputation for the solenoids 'sticking' in the closed position. Get the workshop to cycle the solenoids and check that they all move.
Other than that, its most likely a wheel sensor.
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I think that this is the same system that is on my 1991 216. I had issues with the light coming on over the winter. At this time the car was only used once per week. Now the car is used every day the ALB light rarly comes on.
I think the problem is not helped if the brake fulid is not changed regually, though it seems that electronic sensors tend to fail not the whole ABS unit.
I once was told that it would cost around £400 for a new unit to be installed.
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The hydraulic ABS unit on the 620i (similar to old Honda Accord) used to cost about £2200. High pressure hydraulic systems are never cheap.
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Thanks for the replies. I was surprised to see this old thread from 2003 again. In the end the solution was: Get the council to take the car to the crusher!! In the end the body fell to bits.
Mike
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Light coming on in the winter? When this happened to my wife's Honda Legend intermittently I puzzled under the bonnet for a day or two and then one frosty morning realised the fluid had gone slightly cloudy. The water finding its way into the fluid through hygroscopic action was freezing slightly and seemed to trigger the ABS light only on the coldest days. Fluid hadn't been changed in the two years since we had the car and who knows when before that. Could be worth a try with a fluid change.
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