The check engine light has been on as I am trying to fix a p0170 issue so , Yes the light is on but No I didn't check for a new code.

If I disconnect both front ABS Hub sensors... what happens?
IU'm trying to troubleshoot an occasional banging that my daughter gets when she decelerates. Funny thing is, it only happenes just as she is almost at a dead stop. I drove it and I can only get it to rap twice before stopping , she says sometimes it does it several times before stopping. BUT always just at the end of a stop. and usually on a downslope.
I'm thinking, Suspension movement but all feels tight when up off the ground. I thought something with teh brakes and rotors. They were almost due so I changed them. I'm thinking Trani mount or motor mounts but they are good. So I was thinking maybe she gets an occassional kick from a false ABS sensor. Can I disconnect them and drive without issue?

 

Pull the abs fuse instead. its much easier.

 

I don't have the manual or the car in front of me.
Daughters car..kids work several jobs when they are not at school so I have limited time to actually maintain the cars. I must be the only guy who regularly does Midnight oil changes and brake jobs.

Is this fuse in the drivers door or the Fuse box under the hood? year 2000

 

She just pulled in the driveway... To answer my own question.. Fuse 22 inside the Door.
It seems to have stopped the issue. Now, why would the ABS kick in on such specific scenarios and not all the time?
It seems to react when braking on a slight decline hill and only at the last 15-20 of breaking. The tires are not locking up. Air pressure is equal, tires are same make , model. It just started happening out of nowhere.

 

Simple fix for a known issue. Here is the GM TSB on low speed ABS activation:

Brakes - Low Speed (Below 5 MPH) ABS Activation

Bulletin No.: 02-05-25-006B

Date: January 05, 2006

TECHNICAL
Subject:
Antilock Brake System (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

Supersede:

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.

 

Perfect. Prior to reading this I went to a friends Shop and he plugged in his magic computer.. My OBD2 reader didn't show anything. anyway his read that the one front wheel had an intermittent loss of signal. Probably due to air gap. Anyway, I planned on swapping out this relatively new sensor with the original ones that came off the car. I replaced the hubs about 6 months ago.. Sensors came with the hubs. As I'm doing the swap I noticed the Sensor I was taking off the Hub had several shims under it. I only remember one shim on the old ones when I disassembled them. I put on the old sensor and after a test run, it seems fine. I bet who ever built this new hub just wasn't careful and too many of these washer/shim things ended up being installed, leaving too much of a gap. I ran a test on the sensor I took off with a meter and a piece of metal... the sensor appears to be functioning.
If I read this sooner, I probably would have just pulled the sensor out of the hub and found the Washers..BEFORE unbolting the 3 sensor wire holding points.

Thanks

 

The shims are there to achieve the proper air gap between the sensor and the tone ring inside the hub assembly. If you remove too many shims, the sensor will contact the tone ring and destroy the sensor and the tone ring, then it's time for a new hub assembly. It's obviously too far from the the ring now, so maybe just remove one shim. Then rotate the hub by hand and make sure the sensor is not contacting the ring, (you'll hear or feel it if it is).