I have a friend with a 94 geo prizm - 194K. The ABS for no reason at low speeds would suddenly engage in dry conditions, one day I was riding with him when it happened. It felt like the right front caliper reacted to the ABS (when it went active), while the left did not. He said the ABS light would come on most of the time, but every now and then it would not on start up and then come back on the first time he hit the brakes. I am thinking it is a problem with the left wheel speed sensor, but the car is too old to pull the code at autozone. Is there a way to pull the BCM code with out a scanner to confirm? I am not concerned about no ABS, but the fact that it is picking and chossing the times it wants too does, if it did it in a rainy situation, he could hydroplain. Tig7633 wrote:Is there a way to pull the BCM code with out a scanner to confirm?
nope. u need a obd1 scantool with abs function.
if the abs lite dont come on at startup and the system dont run a self test, u could be looking at a problem with the abs computer or hydraulic modulator.
but before u get into all that, one thing u can do is a visual check of all the wheel sensors. on a older car, and especialy on the front wheels, the wires can break cause of the turning action of the wheels. so see if the wires are either broke or got worn insulation. wheel speed sensors are real sensitive to interference and a exposed bare wire can be enough to yuck up the signal and set a code.
allso look at the face of the sensors. since there magnetic, bits of metal that wear off of the brake rotor during normal use can stick to the sensor, and again that interferes with the signal. dirt from road splash can cause a problem too, so even if u dont see metal on them, sometimes just cleaning them off can help.
if these 'low tech'
things dont work, your gonna have to get your hands on a scantool that reads abs codes, or take it to a place thats got one. Connie's right as rain.
You'll either need a Tech 1 scan tool or a high end scan tool with ABS diagnostic capabilities to find out what codes the EBCM is storing. That is what I thought. I know when he got the the car I had to repair the left sensor wire - I will start there. Yhen try a few other things. If that doesn't work.....he will have to get the code read. the wheel sensor wire aint designed to be repaired. its actualy more like a sheilded coax cable then a regular electric wire. cause of that, and cause of being real sensitive to interference, its pretty much impossible to repair them so they work right.
the proper fix is to replace it. unfortunately on this car the sensor and wire come as a assembly and it runs over $200
the sensor may be the only problem or there may be more then one thing going on. the only way to know for sure is to get codes scanned. but even if there is another problem and it gets fixed, if the abs computer is getting a bad signal from the sensor, the system still wont work. Well I plan on pulling out the sensor and checking the wires for continuity first, if I get anything unusual - he will have to chose what he is going to do. Is there a way to disable the ABS safely till he can make the proper repair? I was thinking of pulling the relay or disconnecting both sensors - so it does not complete the start up check and disables it. He already has a grocery list of repairs and is trying to fix them one at a time. Nothing really critical, but I pick cars to death - especially when I may have to ride in them! AA is great, but I hate waiting for them! Wheel bearings loose at all?
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