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Does anyone know how to check the voltage outputs of the abs sensors on an old honda Prelude? Problem: Alb warning light comes on and stays on after car has travelled a few metres, perhaps indicating sensor fault. Where exactly do I put multitest meter probes? What should meter reading be doing and would you be turning roadwheels in turn by hand with engine running? I don\'t have access to an oscilloscope. Any knowledgeable help appreciated. Cheers, Mike.
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This article could be just what you are looking for:
www.icelord.net/honda/repair/Anti-lock%20brake%20s...f
To summarise, the output from the sensor is an alternating voltage, the frequency of which is proportional to the rotation of the wheel. Ideally an oscilloscope would be used, but otherwise a multimeter set to a low-voltage AC range should tell you whether the sensor is operating or not.
In fact, the article describes a method of reading the diagnostic codes from the ABS unit by configuring it to flash the ABS warning light in certain patterns representing the fault code.
Hope this helps. Unfortunately I know nothing at all about Hondas, I just found the article when I was trying to find out detailed information about how ABS worked.
Tim
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Interesting article Tim.I've got the 86 prelude and the set up seems similar to the later one.Mike
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I have read that the resistance in ohms can be measured across the sensor and compared with another ("good") sensor to isolate a duff one. Tweaking the lead whilst measuring would help shake out any intermittent cable faults.
HTH
rg
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Quite right Rob. A good sensor should show a resistance of around 1000 to 1500 ohms. Simply disconnect the sensors and measure them all. The odd one out is the faulty one.
I'd be interested to know how to measure the output of the sensors whilst driving!! Surely it would be better to pay a garage £20 to interogate the ecu memory for the fault code and then go away and fix it yourself?
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Yes Rob, this is true,but apparently it is necessary to read the output voltages,to check that the pulsar (the thing wots got teeth on it) is working with the sensor.Mike
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Mikey Jay,
I have an intermittent ABS light on problem with my Vx Monterey at the moment. It's similar to yours: Occasionally goes on after 500mtrs or so, usually after turning from one lock to another (lead??)
My plan is as follows:
Clean the cog thingie (brake cleaner) and sensor head (which tends to collect iron filings)
Check resistance of each sensor to locate faulty one.
Swap that one out.
I am puzzled as to why you would want to check the output when the car is moving. Am I missing something?
HTH
rg
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Also check that the sensor is in 'field' for a full revolution of the wheel while turning the steering lock. These sensors ( i believe)have to be physically close enough to the toothed gear to operate reliably, increased wheel speed can lead to unreliable operation of the pick up.
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jud,will do. A worn knuckle can cause problems.
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Checking sensor resistance alone is insufficient as everything depends on output waveforms. I suppose I want to fix it myself because it might cost more than the car is worth to fix. I will have to plod thru my £60 manual (Hayne's) dont do one for Prelude. ABS can be tricky.If I carry on like this for much longer I MIGHT HAVE A TOTAL SYSTEMS FAILURE!!! I would certainly buy another Honda. Mike.
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