2003 silverado 39,ooo miles. due to a shuttering problem at low speed braking Ireplaced both front hubs and sensors at 24,000 miles in 2006. In late 2007 problem returned and abs light came on.Codes showing were co222,223,265,226,and269. I had those erased and only226ame back. I replaced L.F. sensorand now abs light goes out at times then comes back on with the red brake light warning light. If the abs light goes out the first try at stopping has the low shuttering pedal.Brakes seem fine when the red brake light is on. I tried cleaning both sensors and now shows 6 codes. co222 co223 co226 co227 co229 and co269. Does this mean the module is bad?

Sounds to me like you have a bad front hub. The good news is that the wheel speed sensors are part of the wheel hubs. The tricky part can be to figure out which side is bad. If the noise is worse when turning right, it is most likely the left side that is bad. You could try jacking up each corner and shaking the wheels to see if there is any play.

Hi Timothy:
You will want to have it scanned for any trouble codes to see what area the problem may be in. Just let us know what the code(s) are and we can go from there.

The only thing that I can figure is that it may be that the ABS is activating at low speeds, as there is a bulletin that mentions that with no trouble codes. Wheel speed sensors, dirty.

Bulletin No.: 02-05-25-006B
Date: January 05, 2006
TECHNICAL
Subject: Antilock Brake (ABS) Activation At Low Speeds (Clean Wheel Speed Sensor Mounting Surface)

Models:
1999-2000 Cadillac Escalade
1995-1999 Chevrolet Silverado (Old Style)
1995-2000 Chevrolet Suburban, Tahoe (Old Style)
1995-2003 Chevrolet Astro Van, Blazer, S10
1995-1999 GMC Sierra (Old Style)
1995-2000 GMC Yukon, Yukon XL (Old Style)
1995-2001 GMC Envoy, Jimmy
1995-2003 GMC Safari Van, Sonoma
1995-2001 Oldsmobile Bravada

Supercede: This bulletin is being revised to update the correction and warranty information. Please discard Corporate Bulletin Number 02-05-25-006A (Section 05 - Brakes).

Condition: Some customers may comment on ABS activation at low speeds, usually below 8 km/h (5 mph). Upon investigation, the technician will find no DTCs set.

Cause: The cause of this condition may be an increased air gap between the wheel speed sensor and the hub reluctor ring due to rust and debris built up on the sensor mounting surface.

Correction:
Measure AC voltage and clean wheel speed sensor mounting surfaces.
1. Raise the vehicle on a hoist.
2. Disconnect both the front wheel speed sensor harness connectors.
3. Place a DVM across the terminals of each sensor connector.
4. Rotate the wheel with hand speed and measure the ACmV's. The reading should be at least 350 ACmV's.
5. If the reading is between 200 and 350 ACmV's, remove the wheel, caliper and rotor in order to gain access to the speed sensor.
6. Remove the wheel speed sensor and plug the hole to prevent debris from falling into the hub during service.
7. Clean the wheel speed sensor mounting surface using a wire brush, sand paper, emery cloth, ScotchBrite(TM) or other suitable material. Be sure to thoroughly clean the wheel speed sensor surface. There should be no rust or corrosion.
8. Check the sensor head to determine if it has been warped/distorted due to the corrosion build up or other causes. Check the mounting surface on the sensor head for flatness by placing it on the edge of a metal machinists scale or other suitable straight edge to measure the flatness. Check the sensor for flatness in multiple (minimum 3) positions/directions. If the sensor head is distorted, replace the sensor.
9. Apply (spray) two thin coats of the specified rust penetrating lubricant (corrosion inhibitor) to the complete sensor mounting surface on the bearing hub. Allow to dry for 3-5 minutes between coats. Use ONLY Rust Penetrating Lubricant, P/N 89022217 (Canadian P/N 89022218).
10. When the corrosion inhibitor is dry to the touch (about 10 minutes), apply a thin layer of bearing grease to the hub surface and sensor 0-ring prior to sensor installation. Use ONLY Wheel Bearing Lubricant, P/N 01051344 (Canadian P/N 993037).
11. Install either the original sensor or a new one in the hub and secure the sensor. Ensure that the sensor is seated flush against the hub.
12. Install the rotor, the caliper and the wheel.
13. Place the DVM across the sensor terminals and recheck the voltage while rotating the wheel by hand. The voltage should now read at least 350 ACmV's.

Hope this helps; also keep in mind that your feedback is important and I will appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day.

I had a 2001 silverado 2500 h.d. with the same problems. I took it to a gear head and he found that the emergency brake cable was loose causing it to trigger the warning light on the dash. As far as the low fuel guage I took it back to the gear head and he found that the float in the gas tank was broken causing the low fuel light to come on. The float wasnt a big deal until I lost track of mileage and ran the tank dry.

Here is a copy of a GM bulletin that applies to you concerns of low speed ABS activation.

Antilock Brake (ABS) Activation At Low Speeds (Clean Wheel Speed Sensor Mounting Surface) #03-05-25-007 - (09/29/2003)
Antilock Brake (ABS) Activation At Low Speeds (Clean Wheel Speed Sensor Mounting Surface)

1999-2004 GMC Yukon XL

Condition:
Some customers may comment on ABS activation at low speeds, usually below 8 km/h (5 mph). Upon investigation, the technician will find no DTCs set.

Cause
The cause of this condition may be an increased air gap between the wheel speed sensor and the hub reluctor ring due to rust and debris built up on the sensor mounting surface.

Correction
Measure AC voltage and clean the wheel speed sensor mounting surfaces.

Raise and support the vehicle.
Disconnect both the front wheel speed sensor (WSS) connectors at the frame and harness.
Place a Digital Volt Meter (DVM) across the terminals of each WSS connector.
Rotate the wheel clockwise approximately one revolution per second. The minimum reading should be at least 350 ACmV's. If the reading is less than 350 ACmV's, remove the wheel speed sensor. Refer to the applicable Wheel Speed Sensor Replacement procedure in the ABS sub-section of the Service Manual. Plug the WSS bore in order to prevent debris from falling into the hub during service.
Clean the WSS mounting surface on the hub to remove any rust or corrosion using a wire brush, or equivalent.

Important
Make sure that the sensor sits flat on the hub. Check the sensor flange against a straight edge to ensure flatness. If the sensor flange is distorted, replace the sensor.

Apply a thin layer of bearing grease to the hub surface and sensor O-ring prior to sensor installation. Use ONLY Wheel Bearing Lubricant, P/N 01051344.
Install either the original sensor or a new one in the hub. Ensure that the sensor is seated flush against the hub. Refer to the applicable Wheel Speed Sensor Replacement procedure in the ABS sub-section of the Service Manual.
Place the DVM across the sensor terminals and recheck the voltage while rotating the wheel. The voltage should now read at least 350 ACmV's.

Good luck and thank you for using Fixya.

most likely you have a wheel sensor going out. The only way to tell which one is with a data scanner that can access the ABS system.

It will see all the tires spinning at the same speed until one shows a different speed.

Also make sure you have all the same tires and the air pressures are the same.

Try to get the front wheels balanced.

1. Raise and support the vehicle.
2. Remove or disconnect the following:
   
   Tire and wheel assembly Caliper and rotor Wheel speed sensor and brake hose mounting bracket bolt from the steering knuckle Electrical connection for the wheel speed sensor Front drive halfshaft assembly on four wheel drive models Hub and bearing assembly mounting bolts Hub and bearing assembly O-ring seal from the steering knuckle bore (2500 series)
   
3. Clean and inspect the O-ring seal

To install:

1. Clean all corrosion or contaminates from the steering knuckle bore and the hub and bearing assembly.
2. Install the O-ring to the steering knuckle (2500 series).
3. Lubricate the steering knuckle bore with wheel bearing grease or the equivalent.
4. Install or connect the following:
   
   Hub and bearing assembly Hub and bearing assembly mounting bolts. Tighten the bolts to 133 ft. lbs. (180 Nm). Front drive halfshaft assembly on four wheel drive models Electrical connection for the wheel speed sensor Wheel speed sensor and brake hose mounting bracket bolt to the steering knuckle. Tighten to 106 inch lbs. (12 Nm). Rotor Tire and wheel assembly.

You can go to autozone.com and register for free online repair manual with everything you need.

Check the speed sensors at each wheel. http://www.ehow.com/how_4521137_replace-abs-wheel-sensor-chevy.html

in these trucks if the front abs activates at low speeds it is normally because of the wheel speed sensors in the front hubs. easy fix is to remove wheel speed sensor from wheel bearing. clean and file cast surface of bearing to allow sensor to move closer to internal reluctor ring. what happens is over time the casting rusts and creates a larger gap. please rate if this works.

The most likely cause is rust buildup under wheel speed sensors causing them to dislodge(lift up) from front hubs and read incorrectly. If recall has been performed to fix this problem...You may have to replace the appropriate hub in order to stop the ABS activation at low speeds. Let me know if i can help more.