My brakes were replaced about 3 months ago but the brake warning light just came on last night, why? About 2wks ago I had my ball joints replaced and they checked the brakes because of screaching when I would come to a stop. I was told the brakes are fine and sometimes new brakes will make that sound.

How many miles are on the vehicle since the last time the brakes were serviced? Are the brakes squealing? Are the rotors worn out of tolerance, brake pads shot, etc.?

What is the condition of the wheel bearings? Do you experience any "chatter" or slop in the front end when braking or driving? Jack the front end off the ground. Grab tire at 12 & 6 O-Clock and alternate pushing and pulling. Do the same at 3 & 9. Do you feel clunking or any play at all? If yes, then the sensors can often pick this up and interpret it as a loss of traction. Wheel bearings will need to be replaced, and potentially tie rod ends, and/or ball joints.

ABS brake sensors can be loose, bad, have broken wires, or simply "gunked" up with grease, oils and brake dust. If they can't read the tone ring, the result will be an ABS fault to the computer. Inspect integrity and/or try cleaning completely.

ABS Tone Ring could have broken or missing cogs/teeth. Although a bit more rare, this can happen if you have not properly maintained wheel bearings, tie rod ends, ball joints, etc., and/or have hit large rocks or pot holes while driving.

Once these items are inspected, then you'll need to take your vehicle to a service center to have the faults reset.

Here you haven't mention your model name, Go to the given link which is online store known as reliable, they have repair manuals, I am sure you will get the solution Best Manuals

Here is recommended maintenance up to 10 1/2 yrs. If you follow through list, you should be able to tell by elimination what you may need. Here is the link - also list pasted below, here:

http://www.kia-forums.com/2g-2006-2010-rio-rio5/35574-maintenance-schedule.html

SUGGESTED Maintenance Schedule:

Months Kilometres Maintenance Type

4 months 6 000 km Maintenance #1
8 months 16 000 km Maintenance #2
12 months 24 000 km Maintenance #1
16 months 32 000 km Maintenance #3
20 months 40 000 km Maintenance #1
24 months 48 000 km Maintenance #2
28 months 56 000 km Maintenance #1
32 months 64 000 km Maintenance #3
36 months 72 000 km Maintenance #1
40 months 80 000 km Maintenance #2
44 months 88 000 km Maintenance #1
48 months 96 000 km Maintenance #3
52 months 104 000 km Maintenance #1
56 months 112 000 km Maintenance #2
60 months 120 000 km Maintenance #1
64 months 128 000 km Maintenance #3
68 months 136 000 km Maintenance #1
72 months 144 000 km Maintenance #2
76 months 152 000 km Maintenance #1
80 months 160 000 km Maintenance #3
84 months 168 000 km Maintenance #1
88 months 176 000 km Maintenance #2
92 months 184 000 km Maintenance #1
96 months 192 000 km Maintenance #3
100 months 200 000 km Maintenance #1
104 months 208 000 km Maintenance #2
108 months 216 000 km Maintenance #1
112 months 224 000 km Maintenance #3
116 months 232 000 km Maintenance #1
120 months 240 000 km Maintenance #2
124 months 248 000 km Maintenance #1
128 months 256 000 km Maintenance #3


MAINTENANCE #1

MAINTENANCE #1 INCLUDES:

Replace engine oil and filter
Check fluid levels (pwr. strg., brake/clutch, coolant, washer)
Check tire condition and pressure (including spare)
Check exterior & interior lights for proper operation
Check windshield washer/wiper function
Check horn function
Check handbrake function/freeplay
Lubricate all latches, hinges and locks

* = if equipped
See "Model-Specific Maintenance"


MAINTENANCE #2

MAINTENANCE #2 INCLUDES:

Replace engine oil and filter
Check fluid levels (pwr. strg., brake/clutch, coolant, washer)
Check tire condition and pressure (including spare)
Check exterior & interior lights for proper operation
Check windshield washer/wiper function
Check horn function
Check handbrake function/freeplay
Lubricate all latches, hinges and locks
Check engine coolant specific gravity
Check engine air filter; knock out dirt/bugs, replace as req'd
Remove wheels and brake drums, check pad/shoe thickness; inspect calipers, cylinders and shoes for proper function, leaks or damage; adjust rear brakes as required.
Rotate tires
Visually check underbody fasteners for condition & integrity
Check brake/clutch pedal freeplay
Check steering wheel components for proper operation
Check CV boots/tie rods/ball joint boots (visual inspection)
Check all seat belts and anchor integrity
Check exhaust sys. for leaks, mountings, brackets; heat shield
Check transfer case oil level & condition, fill as required
Check front & rear differential fluid, fill as required*
Check man. transaxle oil level & condition, fill as required*
Check auto transaxle fluid level & condition, fill as required*
Lubricate driveshaft u-joints (early Sportage only)
Road test vehicle

* = if equipped
See "Model-Specific Maintenance"


MAINTENANCE #3

MAINTENANCE #3 INCLUDES:

Replace engine oil and filter
Check fluid levels (pwr. strg., brake/clutch, coolant, washer)
Check tire condition and pressure (including spare)
Check exterior & interior lights for proper operation
Check windshield washer/wiper function
Check horn function
Check handbrake function/freeplay
Lubricate all latches, hinges and locks
Check coolant specific gravity
Check engine air filter; knock out dirt/bugs, replace as req'd
Inspect, deglaze, clean, adjust & lubricate brake components
Rotate tires
Visually check underbody fasteners for condition & integrity
Check brake/clutch pedal freeplay
Check steering wheel components for proper operation
Check CV boots/tie rods/ball joint boots (visual inspection)
Check all seat belts and anchor integrity
Check exhaust sys. for leaks, mountings, brackets; heat shield
Check transfer case oil level & condition, fill as required*
Check front & rear differential fluid, fill as required*
Check man. transaxle oil level & condition, fill as required*
Check auto transaxle fluid level & condition, fill as required*
Check idle speed
Inspect power steering lines & hoses (visual)
Check A/C compressor operation and performance*
Check brake line fittings, bleeder screws, booster for damage, looseness, leaks
Road test vehicle

* = if equipped
See "Model-Specific Maintenance"


KIA MODEL-SPECIFIC MAINTENANCE

In addition to the KIA Basic Scheduled Maintenance, certain KIA Models will require the following maintenance services:

ALL MODELS

(Every 36,000 km or 18 months)

Manual transaxle service (except Sportage)
Automatic transaxle service (except Magentis)
Check drive belt condition & tension
Inspect front ball joints

ALL MODELS
(Every 48,000 km or 24 months)
Replace engine coolant
Replace engine air filter
Inspect fuel lines & connections
Inspect ignition wires
Replace spark plugs (except Platinum)

ALL MODELS
(Every 60,000 km or 30 months)
Replace brake/clutch fluid
Inspect EVAP canister & vapour lines

ALL MODELS
(Every 72,000 km or 36 months)
Replace fuel filter
Inspect PVC system/hoses for integrity

ALL MODELS
(Every 96,000 km or 48 months)
Replace spark plugs (Platinum)

ALL MODELS
(Every 102,000 km)
Replace timing belt

SPECTRA
(Every 12,000 km or 6 months)
Replace HVAC air quality filter (if equipped)

MAGENTIS
(Every 12,000 km or 6 months)
Replace HVAC air quality filter (if equipped)

(Every 60,000 km or 30 months)
Automatic transaxle service

SPORTAGE
(Every 36,000 km or 18 months)
Transfer case, differential & manual transaxle service
Transfer case & differential service (auto. trans. model)

SORENTO
(Every 36,000 km or 18 months)
Transfer case & differential service

Upper ball joints are NOT serviced seperatly you have to replace the upper control arm and you probably need to replace the brake pads and rotors at this time also plus the calipers by now.

Yes I know the reason, the Antilock brake system (ABS) hydraulic control unit is defective, if has a sticking valve and must be repalced.

The upper ball joints are replaceable without replacing the control arms. Use Moog K80008 ball joints and a ball joint press.

1. Loosen the wheel nuts slightly. 2. Raise the front of the car and support it with safety stands in the proper locations. 3. Remove the wheel nuts and front wheel. 4. Remove the brake hose mounting bolts. 5. Remove the caliper bracket mounting bolts, and hang the caliper to one side. CAUTION: To prevent accidental damage to the caliper or brake hose, use a short piece of wire to hang the caliper from the undercarriage. 6. On ABS equipped vehicles, remove the wheel sensor wire bracket, then remove the wheel sensor from the knuckle but do not disconnect the wheel sensor connector. NOTE: Use ball joint removers to separate the ball joints from the suspension or tie-rod end. 7. Clean any dirt or grease off the ball joint. Remove the cotter pin from the tie-rod end ball joint castle nut and remove the nut. 8. Apply grease to the special tool on the areas shown. This will ease installation of the tool and prevent damage to the pressure bolt threads. 9. Install a 10mm hex nut on the ball joint. Be sure that the hex nut is flush with the ball joint pin end to prevent damage to the threaded end of the ball joint. 10. Adjust the jaw spacing by turning the pressure bolt. NOTE: If necessary, apply penetrating type lubricant to loosen the ball joint. 11. Once the tool is in place, turn the adjusting bolt as necessary to make the jaws parallel. Then hand tighten the pressure bolt, and recheck the jaws to make sure they are still parallel as pictured above. 12. With a wrench, tighten the pressure bolt until the ball joint shaft pops loose from the steering arm. WARNING: WEAR EYE PROTECTION. THE BALL JOINT CAN BREAK LOOSE SUDDENLY AND SCATTER DIRT OR OTHER DEBRIS IN YOUR EYES. 13. Remove the tool, then remove the nut from the end of the ball joint and pull the ball joint out of the steering/suspension arm. Inspect the ball joint boot and replace if damaged. 14. Remove the cotter pin from the lower arm ball joint castle nut, and remove the nut. 15. Install a 12mm hex nut on the ball joint. Be sure that the hex nut is flush with the ball joint pin end, or the threaded section of the ball joint pin might be damaged by the ball joint remover. 16. Use the ball joint remover, 32mm, as shown to separate the lower ball joint and lower arm. NOTE: If necessary, apply penetrating type lubricant to loosen the ball joint. 17. Remove the knuckle protector. 18. Remove the cotter pin from the upper ball joint castle nut, and remove the nut. 19. Install a 10mm hex nut on the ball joint. Be sure that the hex nut is flush with the ball joint pin end, or the threaded section of the ball joint pin might be damaged by the ball joint remover. 20. Use the ball joint remover as shown to separate the upper ball joint and knuckle. NOTE: If necessary, apply penetrating type lubricant to loosen the ball joint. 21. Pull the knuckle outward and remove the driveshaft outboard joint from the knuckle by tapping the driveshaft end using a plastic hammer, then remove the knuckle. 22. Remove the knuckle from the hub unit. 23. Remove the four flange bolts, then separate the hub unit from the brake disc.

Sounds like you have a bad sensor. No you can not hurt anything by driving with the light on, but you do want to try to keep your warning lights clear

It sounds like the Universal Joints are out on the Driveshaft.