How do I reset the abs system. front brake locking when I switch on ignition. loosens up after a hard pull

gm had a problem with the abs systems on their 1999 trucks and cars the sensor seat would corrode and move slightly enough to set off the low speed sensor of the abs usually goes off at 5mph and less and doesnt set off the abs trouble code need to remove the front wheels and brake assembly to access the hub and abs sensor also check hub to make sure its ok- in the mean time pull the fuse on the abs ur brakes will go to a normal brake without the abs meaning if u step on brake hard[panic brake] u can lock up tires

ABS = Anti-lock Brake System.
TC = Traction Control System (Engine Control Module).
If the ABS lights on the dashboard permanently the ABS system is faulty. You must access the ABS & TC Electronic Control Units (ECU) memory for pull out all DTC (Diagnostic Trouble Codes), using diagnostic equipment connected to the data link connector of the car. Then you will be full informed about bad pieces (e.g.: front right wheel abs sensor interrupted, ...). After bad pieces replacement you will be able to erase all faults memored by ABS ECU, in other words reset the ABS system and turn off the warning lamp on dashboard.
I suspect bad brake pedal switch, but you should scan the ABS & TC ECU's.

Hope this helps your out. I know the diagram and locator is a bit blurry but hopefully it gets what you need.
Drivers kick panel:
Front wiper 20A - Front wiper system Cigar 15A- Cigarette lighter Audio 10A- Audio, remote control mirror Air Bag 10A -Air bag diagnostics Stop lights- 15A -Rear brake light, high mounted stop light ECU B+ 10A - Shift lock actuator, transaxle controle module, radio, engine control module Room 10A - Interior light, clock, ignition key reminder, rear cargo area light switch ABS 10A- Anti lock brake system control unit ECU IG1 10A - Transaxle control module, shift lock actuator, ABS control unit, DRL unit Meter 10A - Instrument panel, back-up switch, electronics time control module, inhibit switch Turn signal 10A- Hazard switch ,front and rear turn lights, turn indicator IGN1 20A - Ignition switch ABS 30A- ABS pump motor TNS 30A- Tail light, license plate light COOL/FAN 30A- Cooling fan Cond/Fan 20A- A/C condenser fan Starter 15A- Start signal , Fuel pump Blower 25A- Blower Motor SR/ACC 10A - Ignition switch Hazard 15A - Hazard and turn signal light D/Lock 25A- Door locks ABS 30A - Anti lock brake system control P/W RH 20A- Power window motor right hand P/W LH 20A- Power window motor left hand IGN2 25A- Ignition Switch
Engine compartment :
Head 25A- headlights IG 2 30A- Ignition switch IG coil 15A -Ignition coil, condenser,generator IC regulator, diagnostic connector. O2 down 10A- Rear O2 sensor O2 up 10A- Front O2 sensor Fuel pump 10A -Fuel pump unit Injector 10A -Fuel injector ,camshaft positioning sensor, purge solenoid valve, EVAP, IAC actuator, Mass Airflow sensor, EGR stepper motor. fuel pump relay coil, vehicle speed sensor. A/Con 10A - A/C compressor controls, cooling fan BTN 30A- Brake light , high mounted stop light. Tail light LH 10A- License plate light, tail light , rear combo light, instrument panel illumination Tail light RH 10A-License plate light, tail light , rear combo light, instrument panel illumination Head low 15A- Headlight Head Hi 15A-Headlight Horn 15A- Horn

Inside kick panel

ABS - Anti-Lock Braking System And EBD -Electronic Brake-force Distribution In Plain English Posted by: Rohit Khurana March 1, 2010 in Automobile Technology
AdvertisementCarBlogIndia Technology Articles , today I will talk of one of the most talked about safety feature called the ABS And EBD. Again I will try to keep the language simple and human understandable (which non-engineers can also make some sense of), pun intended.
What Is ABS ? Anti-Lock braking System system or ABS is a safety system which prevents the wheels on a moving vehicle from locking up(or cease while rotating) while braking. ABS offers improved vehicle control over dry and especially slippery surfaces by reducing the braking distance but it can also increase the braking distance in case of loose surfaces like snow, gravel etc. Ever since the invention of ABS, it has been evolving and the recent systems not only prevent wheel locking but also electronically control the front-to-rear brake bias, which we know as Electronic brake force system, Traction control system, Emergency brake assist or Electronic stability control.
Working Of ABS
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When brakes are applied under heavy loads, the braking pressure becomes high resulting in heavy braking or in other words locking up of wheels. The ABS overcomes this by monitoring the wheel speed and releases pressure on each wheel brake lines in the form of rapid pulses switching between different brake lines. which prevent locking-up.

Preventing lock-up under heavy braking helps the driver in maintaining control over the vehicle. In modern ABS an individual brake line is provided for each of the four wheel enabling different braking pressures for different road surfaces of the wheels.
What Is EBD ? Electronic brake- force distribution system also called as Electronic brake-force limitation is an automobile brake technology that automatically varies the amount of force applied to each of a vehicle's brakes, based on road conditions, speed, loading, etc.
EBD system is always coupled with anti-lock brake-force system. The most important function of EBD is to maintain vehicular control with variation in braking pressure applied to each wheel in order to maximize stopping power. Generally most of the weight of all vehicles is carried by the front end so the EBD ensures less braking pressure at the rear end to avoid skidding. But in some EBD's the distribution of braking pressure at the rear end is more initially when the brakes are applied before the effects of weight transfer comes into play.
Working of EBD system An EBD is a subsystem of the abs and its function is to control the effective adhesion utilization by the rear wheels. this definition has been given by SAE in its technical paper no. #920646.
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The Antilock brake force system releases pressure in different brake lines at the time of heavy braking to prevent locking-up. The action comes in the form of releasing pressure from the braking circuit when it detects extreme and rapid deceleration in any of the four wheels in order to make sure that the driver maintains control over the steering during panic or emergency braking. For example if the wheels of a vehicle are on snow as well as asphalt then in case of emergency braking the ABS will monitor the speeds and eventually the EBD system will release less pressure for wheels on snow and more pressure for wheels on asphalt to prevent wheel lock-up

ABS - Anti-Lock Braking System And EBD -Electronic Brake-force Distribution In Plain English Posted by: Rohit Khurana March 1, 2010 in Automobile Technology
AdvertisementCarBlogIndia Technology Articles , today I will talk of one of the most talked about safety feature called the ABS And EBD. Again I will try to keep the language simple and human understandable (which non-engineers can also make some sense of), pun intended.
What Is ABS ? Anti-Lock braking System system or ABS is a safety system which prevents the wheels on a moving vehicle from locking up(or cease while rotating) while braking. ABS offers improved vehicle control over dry and especially slippery surfaces by reducing the braking distance but it can also increase the braking distance in case of loose surfaces like snow, gravel etc. Ever since the invention of ABS, it has been evolving and the recent systems not only prevent wheel locking but also electronically control the front-to-rear brake bias, which we know as Electronic brake force system, Traction control system, Emergency brake assist or Electronic stability control.
Working Of ABS
Advertisement
When brakes are applied under heavy loads, the braking pressure becomes high resulting in heavy braking or in other words locking up of wheels. The ABS overcomes this by monitoring the wheel speed and releases pressure on each wheel brake lines in the form of rapid pulses switching between different brake lines. which prevent locking-up.

Preventing lock-up under heavy braking helps the driver in maintaining control over the vehicle. In modern ABS an individual brake line is provided for each of the four wheel enabling different braking pressures for different road surfaces of the wheels.
What Is EBD ? Electronic brake- force distribution system also called as Electronic brake-force limitation is an automobile brake technology that automatically varies the amount of force applied to each of a vehicle's brakes, based on road conditions, speed, loading, etc.
EBD system is always coupled with anti-lock brake-force system. The most important function of EBD is to maintain vehicular control with variation in braking pressure applied to each wheel in order to maximize stopping power. Generally most of the weight of all vehicles is carried by the front end so the EBD ensures less braking pressure at the rear end to avoid skidding. But in some EBD's the distribution of braking pressure at the rear end is more initially when the brakes are applied before the effects of weight transfer comes into play.
Working of EBD system An EBD is a subsystem of the abs and its function is to control the effective adhesion utilization by the rear wheels. this definition has been given by SAE in its technical paper no. #920646.
Advertisement
The Antilock brake force system releases pressure in different brake lines at the time of heavy braking to prevent locking-up. The action comes in the form of releasing pressure from the braking circuit when it detects extreme and rapid deceleration in any of the four wheels in order to make sure that the driver maintains control over the steering during panic or emergency braking. For example if the wheels of a vehicle are on snow as well as asphalt then in case of emergency braking the ABS will monitor the speeds and eventually the EBD system will release less pressure for wheels on snow and more pressure for wheels on asphalt to prevent wheel lock-up

you have to check the wires going to the abs, could be a bad wire, if they are ok then either the new sensor is malfunctioning, or the abs sentral is fried

If you have ABS fitted - it could be that it has detected a leak (yes - you bled them) - but in this case it has sealed off the (defective) rear wheels, and is just giving pressure to the front.

If you turn your ignition on - and it comes up ABS light, then I'm afraid you need a scanner to reset the ABS system as it has now probably locked up in this position.

Just another way for dealers to grab your wallet. Sorry.

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

There is a problem in the Antilock brake system and it has shut the ABS down. You will still have normal brakes just no ABS.

The 4WABS is self-monitoring. When the ignition switch is placed in the RUN position, the ABS module carries out a preliminary self-check on the anti-lock electrical system indicated by a 3-second illumination of the yellow ABS warning indicator in the instrument cluster.
If the vehicle is over 10,000 GVW, the warning indicator may remain on until the vehicle is driven at a speed above 15 mph for 10 seconds. Bringing the vehicle up to this speed enables a system self-check that turns the indicator off if no fault conditions are present.
A self-test of the solenoid valve coils and the pump motor is carried out when the vehicle is started. During starting, the brake pedal must be released to run the self-test. If the brake pedal is applied or a failed brake switch occurs, the self-test is run at 4 mph regardless of brake pedal position.
The system has 3 speed sensors,one on each front wheel and one in the rear end housing. The one in the rear end housing usually causes the problem.If any metal savings from the rear end gets on the end of it, this will cause this.
Best way to tell though is to have someone with a scan tool that will communicate with the ABS system pull the trouble codes.

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