I have a 2003 z 71chev. suburban and the abs light came on and an electric motor under the vehicle started running. the motor will not go off. i had to remove the positive battery cable to stop the motor. the brakes doesn't seem to to be working improperly. any help would be appreciated. thanks

check the fluid level in powering steering pump or if electrical assist look under dash attached to steering column and test motor and connections --have vehicle scanned for the trouble codes the abs and the power steering should pop up with code most auto stores off this service for free --aslo check under vehicle by abs lines and check wiring for damage -----test hubs up front for wear or possible failure

First you need to have EBCM - electronic brake control module check for DTC'S - diagnostic trouble code's . If the light is on there is a code stored . I think most part stores can do this and for free . After you find out what code is stored , looking up that code in service repair information for diagnostic trouble shooting chart would be next step . There are a few codes too.
DTC C0035 or C0040
DTC C0045 or C0050
DTC C0110
DTC C0131
DTC C0161
DTC C0186
DTC C0196
DTC C0201
DTC C0240
DTC C0241 or P0856
DTC C0244 or P1689
DTC C0245
DTC C0283
DTC C0287
DTC C0290 or C0292
DTC C0455
DTC C0550
DTC C0558

Find the code do the diagnostic's , fix the problem , wiring issue's , a sensor , bad module ,what ever it is . The light will go out then . Here is a sample of code discription .
• DTC C0035 Left Front Wheel Speed Sensor Circuit
• DTC C0040 Right Front Wheel Speed Sensor Circuit

i think the CU for ABS control needs reprogramming or check the brake circuit for any air pockets.check the under body contacts of ABS

Have the ABS Distribution Unit/Computer checked at the dealer.

NOTE: ABS Unit located under the vehicle, under the drivers seat. Listen to it with the vehicle running with no brake on... if you hear ABS motor running continuously, unplug ABS fuse in fuse block under hood to turn ABS motor off and be able to use vehicle in the meantime whether you decide to get the ABS fixed or not.. This will not affect brake operation, but will disable ABS feature. ABS and Brake idiot lights will remain on. No way to turn them off short of having the correct repair done. ABS Distribution Unit/Computer is very expensive part and requires expensive labour for replacement.

Remove the ABS maxi-fuse (Large fuse) located in the under hood electrical center. In the event you cannot locate that fuse, you can unplug the ABS pump two wire connector at the ABS pump motor located under the vehicle.
Good luck

A relay controls the ABS motor. You can trace the wires running to it. The next time you shut the engine off unplug the relay. If that shuts it off get a new relay for the old one will not open its circuit to shut off the motor to the ABS motor

what you have is a ABS module that has shorted out internally. you have to replace that module and then bleed the ABS pump AND the brakes at all wheels.

No doubt the control module is out, and it continue to operate when the ignition key is off due to a circuit fault. You can disable it easily by pulling the 60 amp fuse in the under hood fuse box (it is listed on the panel as ABS). Note that this disables the ABS braking feature and traction control, so be very careful when driving. The part can be purchased on the GM global parts site, about $600-$700 for the module. This will be the second time this has gone out for me and GM is not sympathetic, rather "pathetic", for a part to fail so often.

Just serviced my own 4x4 Suburban, by buying a 2nd hand encoder motor and replaced the old one, which was trashed by the winter salt. The device is prone to failure since it's made of alluminium and water has an easy time of entering the unit and trashing it.

CAUTION: Abbreviated gratuitous information of how an encoder motor was serviced. If unqualified to deal with repair, seek professional service.
CAUTION: Read at one's own risk.

To replace it, you need to crawl under the vehicle and remove the front drive shaft;

Disconnect the electric harness to the encoder motor, followed by unbolting it.

Take replacement encoder motor and install. There may be an issue with aligning the cogged cam of the transfer case to the encoder motor. If so, the vehicle's 4 wheels will need to be raised off the ground. The engine started, transmission in Park, and using a Vice-Grip® wrench gently rotate cam clockwise approximately 1/16 to 1/8 of an inch, then while set in this position, stop engine. Now attempt to align and attach the encoder motor.

After successfully attaching new encoder motor, attach its wiring loom.
Test vehicle.

i serviced my 2004 yukon for abs light came on they told me it was the right front abs speed sensor wire , which is sold sepratly or with wheel hub cost$ 300 or 57$ for just sensor wire, i did all brakes changed sensor and for awhile the stayed off but comes on and at about 20 mph it turns off ?