ABS not working
 

so cruising down a local road during heavy rain, I hit a water patch with my track tires while braking and locked up my wheels. I lost all traction and started sliding sideways then round and round. luckily nobody was around and nothing happened to the car.

then it occurred to me, wtf happened to my ABS? I then did some trial run at a large parking lot when it was dry and sure enough, I have no ABS. All 4 tires lock up and I don't feel any ABS modulation at the brake pedal. I checked all the wires: IGN 12+ wire, brake 12+ signal, two ground, and two constant 12V from alternator are all reading correct voltage at the ABS harness end. my speedometer is working correctly, so I must assume the ECU wires and all 4 wheel speed sensors must be fine.

I should mention this is a used rx8 ABS pump from ebay which I relocated to the front of the car for various reasons. My original one was damaged. Do I have to do anything to the ABS pump and module from another rx8 to make it work appropriately after install? from my understanding, the functions of the ABS pump is completely controlled by the ABS module attached to the ABS motor, and it receives no input from the ECU. It just has 2 wire output to the ECU which as I understand are for speedometer. I have no DSC.

any thoughts? thanks all.

ABS Module has to be coded to the ECU. If the pump was the problem then you can use your old module with the new pump and avoid the re-code.

damn thanks. I tossed my old module along with the pump... I guess I'll call the dealership. thanks for the info.

so I miraculously found my original ABS and that's back on the car. still the wheel locks up in parking lot test. I double and triple checked all ABS wiring. I have no ABS light on dash.

where do I go from here? I searched around and everyone seems to have issues with the ABS light turning on the dash. Nobody talks about actually locking up the wheels when there is no abs light. Do I need to reset anything? or drive around for awhile to get it to work? I frequently disconnect battery for various reasons. thanks in advance.

any help would be appreciated.

Sorry wasn't watching this thread. The abs unit has two parts the electronics and the hydraulics. Now what parts of the old ABS have you put back on the car? Also did you bleed the system after?

I just changed the electronic module part with bunch of these solenoid piston things. I left the motor and lines alone... there is good hydraulic pressure, so I didn't bleed it yet.

Ok just trying to get the whole picture.
Original ABS got damaged on the hydraulic side.
Replaced the whole thing with a used unit.
It then had all the warning lights and nothing worked.
Then replaced the electronic side with the original unit.
Now no warning lights and brakes lock up.
Is that right?

What made you think the original unit was damaged? Physical damage? Quit working?

If you have no warning lights it means the system thinks it's fine. It tests the pump and valves to all 4 wheels on a cold start. If it's passing this but locking up the wheels then I'm at a loss.

I changed the original unit because I just had an extra one from a newer year rx8 and I just thought why not. I didn't know anything about module having to match up with the ecu. now I have the original abs module back on the car.

yea to be clear, I do not have ABS light. ABS is connected. all my 3 rear brake lights work. brake switch works.

still, when I brake hard on a short stretch of unpaved road leading to my house, the wheels lock up.

thanks for your input. it's a bummer... some say it just needs time to reconfigure (6 drive cycles?). i'm just hoping for the best.

I see someone, Harlan, said the ABS module has to be coded to the ECU. Could this be the problem I am having with my 2004 RX8. I recently had to have the computer re-flashed now the ABS and traction control lights have been on (were not on prior to re-flashing). Tried a couple of different options including turning the wheel counter clockwise all the way and then clockwise to clear it and also checked the fuses, but these did not clear the lights. How do I go about coding the ABS module to the ECU, and could that be the problem?

If it is due to re-flashing the ecu then you need to go to a dealer or to someone with IDS to make your system whole. How was it reflashed? Mazda edit and AP don't cause this problem.