ABS sensor Test Points?
 

The FSM shows testing each ABS sensor at it's connection, 2 under the hood and 2 under the bins. Then later it shows testing all 4 at the ABS cpu in the rear hatch area.

Can you test at the cpu and Not have to get under the bins? Or are you testing something different by testing the pins there vs the connectors?

The under hood ones are easy, hate to keep taking the bins out as each time is another chance for plastic breaks.

Thanks for any insight

What's wrong with your sensors/ABS? The ABS system is pretty darn hardy.

It's just wires from the sensors to the ABS computer, you can easily test continuity on those wires if you have a long enough lead on your multimeter.

Most common problem I've heard of is broken/torn wiring by the sensor from road debris, a wreck, or pulling on it while working on the car.

Dale

We have an ABS light that's been solid on forever.
Need to see if it's one of the sensors or the cpu

Trying to figure out if testing at the CPU will give the same info
as testing under the bins.

I would think so. I'd do a visual on all the sensors to start with. Next thing would be testing the relays in the ABS pump, which is outlined in the shop manual.

The computer itself is most likely OK, that's a hardy unit and out of the elements, I doubt that is going to be your issue.

Not sure if there's some other test procedure to get the light to flash a code or something. The shop manual just shows how to use the expensive Mazda tool to check things out.

BTW, I've been on a roll with your questions lately :).

Dale

Dale,
Yes you have. Thanks for all the Experienced answers.

The flashing light option is not available on the '93, but is later -- wish I had that tool.

I'll check the pump relay today.

Test each sensor at their connectors, testing from the ABS cpu just checks for continuity through the wiring harness, not the resistance of the sensors. Also, check to make sure the ABS pump is getting power (FSM P-51), this is what was wrong with mine, my connector had a corroded pin. I would check those and see what you come up with, but, like Dale said it is a pretty robust system.
When does your ABS light come on, as soon as you start the car or when you start moving?

Thanks.

ABS light is on from the time you turn the key, never goes off.
It has been that way for a long time, just getting to it.

I would start with your relays and fuses, then check your sensors and wiring. If it was a wheel

speed sensor I would think that would throw the light when you start moving. If everything

checks out and you want to test another ABS cpu pm me, I have one laying around you can try.

Ended up replacing the Control Unit/Pump since it was leaking.

That also eliminated the ABS light, so good to go now.

Oh Well -- no ABS light for 50 miles, then it popped back on again.

Back to the drawing board

For further readings of this thread, answer is at P-59 of FSM.