88 c1500 would like to disconnect rear wheel anti lock system.showing no codes rear wheels constantly locking up at low speeds .

You need a mechanic with a high level scan tool to check the Diagnostic Trouble Codes and Live Data. It is probably ABS Sensor related, but should never leave you with no brakes..

Hi!! Yes, your vehicle is equipped with Anti-Lock Brake System. The Teves Mark II Anti-lock Brake System (ABS), used on 1987-90 GM Bonneville, Eighty Eight and LeSabre vehicles , is manufactured by Alfred Teves Technologies of West Germany. The 4-wheel system uses a combination of wheel speed sensors and a microprocessor to determine impending wheel lock-up and adjust the brake pressure to maintain the best braking. This system helps the driver maintain the control of the vehicle under heavy braking conditions.
A HELPFUL - 4 THUMBS - rating for this solution would be greatly appreciated. Thank you for using FixYa.

Check Brake fluid level.

When the ABS light is on, the brakes should revert to standard braking.

The only time ABS should invoke is when the tires are slipping as sensed by the wheel speed sensors when the wheel locks up on any of the axles.
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ANTI-LOCK BRAKE SYSTEMS General Information Fig. 1: RWAL brake system diagram
Fig. 2:4WAL Component locations — except 1996 models
p>Fig. 3: 4WAL Component locations — 1996 models Fig. 4: Three sensor 4WAL brake system diagram — Except 1996 models
Fig. 5: Four sensor 4WAL brake system diagram — Except 1996 models
There are two basic types of anti-lock systems available for this vehicle; a Rear Wheel Anti-Lock (RWAL) brake system and 4 Wheel Anti-Lock (4WAL) brake system. The 4WAL system has two variations; a 3 sensor system and a 4 sensor system. The 2WD vehicles will be equipped with the 3 sensor system, but the AWD vehicles can be equipped with either. The systems are easily identified by looking at the rear wheels for a sensor harness. If there is a sensor harness and thus, rear wheel sensors, it is the 4 sensor system. If the vehicle is not equipped with a harness, it is the 3 sensor system. The 4 sensor system takes it speed references from each of the wheels. The 3 sensor system takes its speed references from each of the front wheels and the vehicle speed sensor located in the transmission (2WD) or the transfer case (AWD). The RWAL system components consist of the Vehicle Speed Sensor (VSS), the Electronic Control Unit (ECU), the isolation/dump valve and the Vehicle Speed Sensor Buffer (also known as the Digital Ratio Adapter). The ECU also receives signals from various brake switches. The 4WAL system components consist of the Electro-Hydraulic Control Unit (ECHU) valve (also known as the Brake Pressure Modulator Valve or BPMV), the wheel speed sensors, Vehicle Speed Sensor (VSS) on 3 sensor systems and the VSS Buffer.

you have one on the inside of each wheel.
SECTION 206-09A: Anti-Lock Control 2002 Lincoln LS Workshop Manual
REMOVAL AND INSTALLATION Front Wheel Speed Sensor
Material Item Specification RTV Silicone Sealant
FSTZ-19G204-AB (Canada CXC-114A) NAVSTR Sealer
Removal and Installation

1. Raise and support the vehicle. For additional information, refer to Section 100-02 .

1. Position the inner splash shield aside.
   1. Remove the pin-type retainers.
   1. Position the inner splash shield aside.

1. Disconnect the anti-lock brake sensor electrical connector.

1. Remove the anti-lock brake sensor harness from the brake hose clips.

1. Remove the anti-lock brake sensor.
   1. Remove the anti-lock brake sensor clip.
   1. Remove the anti-lock brake sensor.

1. NOTE: Make sure the anti-lock brake sensor is fully seated before installation of the new clip.
   To install, reverse the removal procedure.
   • Apply a 2.5 mm (0.1 in) bead of silicone sealant to the outside diameter of the anti-lock brake sensor.

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Rear Wheel Speed Sensor Removal and Installation

1. Raise and support the vehicle. For additional information, refer to Section 100-02 .

1. Disconnect the rear anti-lock brake sensor electrical connector.

1. Remove the rear anti-lock brake sensor harness from the control arm clips.

1. NOTE: Clean off dirt and foreign material that may have collected around the rear anti-lock brake sensor before removal.
   Remove the rear anti-lock brake sensor.
   1. Remove the anti-lock brake sensor bolt.
   1. Remove the anti-lock brake sensor.

1. To install, reverse the removal procedure.

adjust your rear shoes up so that the rear drums just turn, with them ajusted to a low setting the brake pedal will be low .
also when you start your engine it is noral for the pedal to drop because of the boster ! [ but not to the floor ]
Bruce Pike

you need someone to scan it for codes but it sounds like the speed sensor for one of the wheels is droping the signal to the abs unit at lower speeds they can see that with the data stream with a scanner

I would pull the fuse for the ABS hydraulic pump and then put it back in and see what happens. Don't ever recall a pump running. Dealer may need to hook up scan tool for diagnostic fault codes, DTCs.



Principles of Operation
The ABS control module receives wheel speed readings from both front wheel speed sensors and the rear differential speed sensor, and processes this information to determine if an ABS event is necessary. The wheel speed sensor electrically senses each tooth of the ABS sensor indicators as it passes through the wheel speed sensor's magnetic field.
The ABS control module continuously monitors and compares the rotational speed of each wheel speed sensor indicator and, when it detects an impending wheel lock, modulates brake pressure to the appropriate brake caliper(s). This is accomplished by triggering the hydraulic control unit (HCU) to open and close the appropriate solenoid valves. Once the affected wheel returns to normal speed, the ABS control module returns the solenoid valves to their normal position, and normal (base) braking resumes.
The ABS control module is self-monitoring. When the ignition switch is turned to the RUN position, the ABS control module will do a preliminary electrical check, and at approximately 20 km/h (12 mph), the pump motor is turned on for approximately one-half second. Any malfunction of the ABS system will cause the ABS to shut off; normal power assisted braking, however, remains.
Inspection and Verification — Scan Tool Communications Check

1. Verify the customer concern by carrying out the Drive Cycle Test.

1. Visually inspect for obvious signs of mechanical and electrical damage.

Visual Inspection Chart Mechanical Electrical

• Parking brake cable
• Tire pressure
• Tire size or mismatched tires

• Blown fuse
• Central junction box (CJB):
  • fuse 23 (10A)
• Battery junction box
  • fuse 102 (50A)
• Connectors or connections
• Ground integrity
• Harness routing
• Wire chafing
• Circuitry open/shorted

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Anti-Lock Control The four-wheel anti-lock brake system (4WABS) consists of the following components:

• Anti-lock brake control module (2C265)
• Front anti-lock brake sensor (2C204)
• Front anti-lock brake sensor indicator (2C182)
• Hydraulic control unit (2C219)
• Rear anti-lock brake sensor (2C190)
• Rear anti-lock brake sensor indicator (2C189)
• Yellow ABS warning indicator

Anti-Lock Control —Vehicles Built After 03/2002 The 3-channel anti-lock brake system consists of the following components:

• front wheel speed sensors
• front wheel speed sensor rings
• hydraulic control unit (HCU)
• Anti-lock brake control module (ECU)
• rear wheel speed sensor
• rear wheel speed sensor rings
• yellow anti-lock brake warning indicator

The 4-channel anti-lock brake system with traction control and stability assist system consists of the following components:

• active brake booster with integral solenoid
• brake booster release switch
• front wheel speed sensors
• front wheel speed sensor rings
• hydraulic control unit (HCU)
• stability assist module (ECU)
• stability assist event indicator
• lateral accelerometer
• longitudinal accelerometer (4x4)
• rear wheel speed sensors
• rear wheel speed sensor rings
• steering wheel position sensor
• yaw rate sensor
• yellow anti-lock brake warning indicator
• brake pressure transducer
• traction control switch

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I suspect the abs issue is causing the speed control not to work if it happened at the same time the cruise control stopped working. When the yellow ABS light comes on, it means the ABS is dactivated. You may have a faulty accelerometer which senses acceleration and yaw (side to side lean). I have not seen a bad one but you said it is sensitive to acceleration.
I would unplug it and see what happens. The connector should have a small tab to depress so you can pull the connector out.
Here is where it is:

Accelerometer Removal and Installation

1. NOTE: The accelerometer is located under the center, rear passenger seat carpet. (I think you have to remove seat for access).
   Cut the carpeting along the perforations.

1. Disconnect the electrical connector.

1. Remove the nuts and remove the accelerometer.

Have dealer hook up tester and pull fault codes if you can't find an easy solution.
Some background info

A malfunction in the anti-lock brake system will cause the anti-lock brake control module to shut off or inhibit the system. However, normal power-assisted braking remains.

Malfunctions are indicated by the yellow ABS warning indicator in the instrument cluster.

The anti-lock brake system is self-monitoring. When the ignition switch is turned to the RUN position, the anti-lock brake control module will carry out a preliminary self-check on the anti-lock electrical system indicated by a three-second illumination of the yellow ABS warning indicator in the instrument cluster.

During vehicle operation, including normal and anti-lock braking, the anti-lock brake control module monitors all electrical anti-lock functions and some hydraulic operations.

Each time the vehicle is driven, as soon as vehicle speed reaches approximately 20 km/h (12mph), the anti-lock brake control module turns on the pump motor for approximately one-half second. At this time, a mechanical noise may be heard. This is a normal function of the self-check by the anti-lock brake control module.

Pedal pulsation coupled with noise while braking on loose gravel, bumps, wet or snowy roads is normal and indicates correct functioning of the anti-lock brake system.

Warning Lamp Indicator
The anti-lock brake system (ABS) uses the yellow ABS warning indicator to alert the driver of a malfunctions in the ABS.
The yellow ABS warning indicator will come on to warn the driver that the ABS has been turned off due to a symptom that exists in the ABS. Normal power assist braking remains but wheels can lock during a panic stop while the yellow ABS warning indicator is illuminated.

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Please report back, I am curious if that is what it is. Good luck

2006 Saturn VUE AWD, same issue - only it was very intermittant and happened at very slow braking (like rolling to a stop sign) when it kicked in. Turned out it too was the wheel speed sensor. Although I had to take it to the dealership 2x, the first time they checked engine codes with no avail, and a visual inspection didn't show anything either. It was only when I happened to take it there on a day that it was happening frequently. They actually had to hook up the diagnostic computer, drive around, and get readings from the speed sensor to confirm it was shot.