Have A 2000 excursion hade the hubs replaced and now have the ABS light going on off?

the speed sensors in the wheel hub control the abs each wheel bearing/hub has a speed sensor you need a good scan tool to pin piont the bad one or ones with gm you have to replace the whole hub/bearing to replace the sensor.

Rear Speed Sensor Center Input Failure

Some type of abs speed sensor on rear diff

May be just dirty connnector

I googled it,would be here all night

Try Google ---2000 Excursion OBD2 Codes -C1230

I have a 2006 chevy uplander that had an abs light coming on so i took it to my local GM dealer to have it diagnosed and they had told me that the hub and bearing assembly needed to be changed, so i changed it and the light still came on. Upon further investigation i came to discover that the abs wires were frayed in two locations and that the connecters were loose i tightened the connecters and replaced the wires and now my abs light does not come on. I also discovered that i did not need a new hub and bearing assembly after all.

ABS light is on due to a bad or dirty ABS sensor on the front wheel hub. Inspect the front wheel ABS sensor and wire leads on the front wheel inner hub where the speed ring is. The 4wd will not disengaged is common when the vacuum switch on top of the transfer case drives side has gone bad and needs to be replaced, you can pick one up at Auto Zone or Napa for around $25.00 and take about 20 min to replace with a wrench. At worst it's going to be a bad electronic Actuator at the transfer case or one of the speed sensor at the transfer case, but most likely it's going to be the vacuum switch if you don't have any Check engine light on. Good luck and keep me posted.

it sounds like your hubs are going bad. when you disengage your 4x4 try backing up a few feet. this might help them release

This is common. the locks due tend to freeze up and need either a greasing or replacement. I do suggest automatic locking hubs that you don't have to turn yourself. You can get the part almost anywhere

Turn on ignition switch and system should chk itself. If all is right the light should drop out..You may have to drive it for the sensors to register presence.

2 areas of concern here involving the ABS light:

1. After replacing the hubs, bleeding the brake lines and replacing spent brake fluid
2. Replace the ABS sensors

Hope this answers your question. Best of luck.
Greg

check the vacuum lines going to the hubs and make sure the hubs are locked in

one is on top the rear diff, and the others are at the front wheels mounted to the hub they just wear out and if you dont replace them your abs will not function