Can a brake job cause the ABS light to come on?

Sounds like it could be related. Have you checked your brake fluid level to see if its low or over filled and also check to see that your emergency brake is released al the way. If thos check out fine then take it back to your mechanic or a new mechanic.

Mechanic says it is unrelated, but it seems very peculiar to me that you take a car in for a break repair and comes back with the ABS light on. Mind you that light was never on before the repair. I guess what I was wondering is that if one is not careful can they knock out the wheel sensors for ABS or somehow impact the ECU for the ABS. I don't know perhaps short something out or damage the sensor structure. Are there any steps that need to be taken to avoid damaging ABS peripherals for this car? BTW, all the fluid levels are fine and the emergency break is all the way down.

I did have a thought some older cars and trucks offered ABS as an option and ABS versus non ABS rotors are diifferent. If the wrong rotors where uses it could trigger the ABS light, and yes it does sound mechanic related. Im going to try and search to see if they offered two different types of rotors and I will let you know what I find.

OK, I searched online and didnt find and difference for the rotors, but did find an ABS speed sensor it is possible that when the job was done they disconnected it or damaged it. Here is link to what the part looks like and replacement cost: http://www.partsgeek.com/catalog/1999/isuzu/rodeo/brake/abs_speed_sensor.html

Thanks Michael. Can you direct me to the link that said if the job is not done right the ABS sensor could be damaged?

You might be able to check the rodeo forums.

OK, I was also able to find the Brake Service Bulletin BPI 04-08 which is suggesting that the source of the problem may be the rear speed sensor corroded or fraying wiring harness, which the mechanic inspected but did not change anything. My guess is that when he put the rear (drum) brakes back together the wiring harness was not properly reinserted.

is it true you should open the bleeder screw when depressing piston back into the capliar with abs

I haven't heard this one , but it could be true. When I replaced my front pads and rotors last month, depressing the caliper plunger back in caused brake fluid to come out from somewhere up top, maybe fill container I think. Now, my ABS light stays on after about 10 seconds of driving and the ABS will not function anymore. It was working fine before my brake changing job. I've dis/reconnected the speed sensor leads and pulled the fuse to check also. I have no other answer but to think that I messed up my ABS system by not opening the bleed valve. Does anyone know how to reset the whole ABS system?

TJ Yes you are correct I just did the same thing with my Rodeo, and my Dad warned me about not doing that, lol, I should've listened to Dad. I'm also looking to reset the system or repair, replace, you know. I hoping I can just use the scanner to look at the codes and see what's going on, I got a scanner from auto zone for 100dls but it suppose to do a lot. I'm hoping I can just wipe the codes clean, we'll see. So, make sure to open the bleeder folks or it could do something to your ABS

There are check balls that are designed to allow brake fluid to travel from the reservoir to the calipers and not the other way. I have been preaching this to as many shade tree mechanics as I can since I learned this in auto tech school years ago. If you push the fluid back up into the system, you can do damage as some of you have found out. By opening the bleeder valve and using a c clamp to push the fluid out and at the last twist of the clamp you close the bleeder, you have one, essentially bled your system, two replaced the old fluid that has gotten hot from numerous braking operations and three, if you only top off your fluid after having done the above procedure you only have to look at the level of fluid to see how warn your brakes are instead of removing the wheel and all. Just a thought.