Antilock Braking System

[davecyr]

I have a 2001 GMC Z-71 4x4. I changed the rear rotors and pads not too long ago and now when stopping it's like the ABS system thinks I'm on ice the last 20 feet or so and it activates. Very dangerous. I have experienced this on other GM vehicles when the sensors have gone bad in the front wheel bearings, but as far as I can determine there are no wheel bearing sensors or any other kind of sensor at the rear axle that I have found on my truck that could have been damaged from this brake cahnge. I have done my own brakes on this truck several times and have never had this happen. My ABS light is not displaying in the dash, but does activate when I pull the fuse so I know the light works. I do have a service engine light that is lit but I think the truck was built with it on so no change there. As far as I can tell nothing else has changed on the vehicle. Any suggestions you can offer would be helpfull. Thank you.

[bobcat5544]

Document ID# 1587153

2001 Chevrolet Chevy K Silverado - 4WD

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Subject: Product Safety - Front Wheel Speed Sensor Corrosion #04094 - (01/25/2005)

 

Models: 1999-2002 Chevrolet Silverado

 

2000-2002 Chevrolet Tahoe, Suburban

 

2002 Chevrolet Avalanche

 

1999-2002 GMC Sierra

 

2000-2002 GMC Yukon, Yukon XL

 

Located in Ontario, Quebec, Newfoundland, New Brunswick, Nova Scotia, Prince Edward Island

--------------------------------------------------------------------------------

Condition

General Motors has decided that a defect which relates to motor vehicle safety exists in certain 1999-2002 Chevrolet Silverado, 2000-2002 Chevrolet Tahoe, Suburban, 2002 Chevrolet Avalanche, 1999-2002 GMC Sierra, 2000-2002 GMC Yukon, Yukon XL vehicles located in Ontario, Quebec, Newfoundland, New Brunswick, Nova Scotia, and Prince Edward Island. These vehicles may have a condition permitting corrosion to occur between the front hub/bearing assembly and the wheel speed sensor. If the brakes are applied while the vehicle is travelling at a speed of greater than 6 km/h (3.7 mph) but less than 16 km/h (10 mph), the corrosion may cause an unwanted anti-lock brake system (ABS) activation. If this condition occurred where stopping distance is limited, a crash could occur.

 

Correction

Dealers are to clean and treat the affected area, and in some cases, replace the front wheel speed sensor.

 

Vehicles Involved

Involved are certain 1999-2002 Chevrolet Silverado, 2000-2002 Chevrolet Tahoe, Suburban, 2002 Chevrolet Avalanche, 1999-2002 GMC Sierra, 2000-2002 GMC Yukon, Yukon XL vehicles located in Ontario, Quebec, Newfoundland, New Brunswick, Nova Scotia, and Prince Edward Island and built within these VIN breakpoints:

 

Year

Division

Model

From

Through

 

2002

Chevrolet

Avalanche

2G100036

2G363592

 

1999

Chevrolet

Silverado

X1100020

X1299247

 

XE100004

XE256732

 

XZ100011

XZ214525

 

2000

Chevrolet

Silverado

Y1100133

Y1405970

 

YE100163

YE433798

 

YZ100149

YZ371921

 

2001

Chevrolet

Silverado

11100142

11407113

 

1E100192

1E336884

 

1F106141

1F211164

 

1Z100191

1Z334358

 

2002

Chevrolet

Silverado

21100156

21419297

 

2E100444

2E305421

 

2F100374

2F240815

 

2Z100416

2Z348298

 

1999

GMC

Sierra

X1500012

X1571383

 

XE500003

XE555865

 

XZ500005

XZ540992

 

2000

GMC

Sierra

Y1100181

Y1403129

 

YE100251

YE433795

 

YZ100185

YZ371911

 

2001

GMC

Sierra

11100139

11407805

 

1E100214

1E336874

 

1F106143

1F211229

 

1Z100174

1Z335044

 

2002

GMC

Sierra

21100194

21419089

 

2E100809

2E305888

 

2F100538

2F241040

 

2Z101557

2Z348466

 

2000

Chevrolet

Suburban

YG100061

YG229022

 

YJ100468

YJ211389

 

2001

Chevrolet

Suburban

1G104020

1G280557

 

1J100301

1J292755

 

2002

Chevrolet

Suburban

2G126599

2G317898

 

2J101267

2J318178

 

2R232620

2R300009

 

2000

Chevrolet

Tahoe

YJ100026

YJ211859

 

2001

Chevrolet

Tahoe

1J100026

1J309634

 

1R100402

1R218091

 

2002

Chevrolet

Tahoe

2J100983

2J325817

 

2R116414

2R313418

 

2000

GMC

Yukon

YJ100166

YJ211823

 

2001

GMC

Yukon

1J103611

1J292565

 

1R100509

1R203664

 

2002

GMC

Yukon

2J184383

2J309025

 

2R116570

2R302224

 

2000

GMC

Yukon XL

YG100003

YG210566

 

YJ100393

YJ210566

 

2001

GMC

Yukon XL

1G101568

1G279527

 

1J101870

1J292644

 

2002

GMC

Yukon XL

2G127091

2G326479

 

2J100796

2J337991

 

2R232816

2R300196

 

Important: Dealers should confirm vehicle eligibility through GMVIS (GM Vehicle Inquiry System) before beginning recall repairs. [Not all vehicles within the above breakpoints may be involved.]

 

For dealers with involved vehicles, a Campaign Initiation Detail Report containing the complete Vehicle Identification Number, customer name and address data has been prepared and is being furnished to involved dealers. Dealers that have no involved vehicles currently assigned will not receive a report with the recall bulletin.

 

The Campaign Initiation Detail Report may contain customer names and addresses obtained from Motor Vehicle Registration Records. The use of such motor vehicle registration data for any other purpose other than follow-up necessary to complete this recall is a violation of law in several states/provinces/countries. Accordingly, you are urged to limit the use of this report to the follow-up necessary to complete this program.

 

Parts Information

Parts required to complete this recall are to be obtained from General Motors Service Parts Operations (GMSPO). Please refer to your "involved vehicles listing" before ordering parts. Normal orders should be placed on a DRO=Daily Replenishment Order. In an emergency situation, parts should be ordered on a CSO=Customer Special Order.

 

Note: Very few vehicles will require front wheel speed sensor replacement; if required, order appropriate part from GMSPO.

 

Part Number

Description

Qty

 

89022218

Lubricant, Rust Penetrating (will service 50+ vehicles)

1

 

00993037

Lubricant, Wheel Bearing (will service 25+ vehicles)

1

Service Procedure

The following procedure provides instructions for repairing a corrosion condition where the front wheel speed sensor mounts on the front wheel bearing assembly.

 

Raise the vehicle on a suitable hoist and support as necessary.

Remove both front tires and wheels.

 

Compress the front brake caliper pistons.

3.1. Install a large C-clamp over the top of the caliper housing and against the back of the outboard pad.

 

3.2. Slowly tighten the C-clamp until the pistons are pushed completely into the caliper bores.

 

3.3. Remove the C-clamp from the caliper.

 

Important: It is not necessary to remove the front brake caliper from the bracket when removing the bracket in the next step.

 

Remove the two bolts that attach the front brake caliper mounting brackets to the knuckle.

Notice: Support the brake caliper with heavy mechanic's wire, or equivalent, whenever it is separated from its mount and the hydraulic flexible brake hose is still connected. Failure to support the caliper in this manner will cause the flexible brake hose to bear the weight of the caliper, which may cause damage to the brake hose and in turn may cause a brake fluid leak.

 

Remove the brake caliper and bracket as an assembly and support it with heavy mechanic's wire or equivalent. DO NOT disconnect the hydraulic brake flexible hose from the caliper.

Mark the relationship of the rotor to the bearing hub.

If equipped, remove the rotor retaining push nuts from the wheel studs.

 

Remove the rotor.

 

Remove the bolt (1) that attaches the wheel speed sensor to the bearing hub.

Notice: Carefully remove the sensor by pulling it straight out of the bore. DO NOT use a screwdriver or other device to try to pry the sensor out of the bore. Prying will cause the sensor body to break off in the bore.

 

Remove the wheel speed sensor from the bearing hub assembly.

 

 

 

Important: The mounting surface on the sensor must be flat in the next step in order to be mounted correctly on the bearing hub assembly. If the mounting surface on the sensor is warped or bent, the sensor must be replaced.

 

Inspect to see if the mounting surface on the sensor is flat. Check the mounting surface on the sensor head for flatness by placing it on the edge of a metal machinist's scale or other suitable straight edge to measure the flatness. Check the sensor for flatness in multiple positions/directions (minimum 3).

• If the sensor mounting surface is NOT flat (1), the sensor must be replaced. Proceed to the next step and replace the sensor.

 

• If the sensor mounting surface IS flat (2), the sensor IS to be reused. Proceed to Step 16.

 

 

 

 

 

Remove the wheel speed harness mounting clips from the knuckle (4) upper control arm (3) and frame (2).

Disconnect the wheel speed sensor electrical connector (1) from the vehicle wiring harness.

Connect the new wheel speed sensor harness electrical connector to the vehicle wiring harness.

Attach the wheel speed sensor harness to the frame, upper control arm, and the knuckle.

 

 

 

Temporarily plug the wheel speed sensor hole (1) in the bearing hub to prevent debris from entering it when you clean it.

Important: All rust and corrosion must be removed from the wheel speed sensor mounting surfaces on the bearing hub in the next step.

 

Using a wire brush, sandpaper, emery cloth, scotch brite, or equivalent, thoroughly clean the wheel speed sensor mounting surface (2) on the bearing hub to remove any rust of corrosion.

Using compressed air, remove all debris from the bearing hub surface.

Using a clean shop towel, clean the sensor and the O-ring.

Important: While the corrosion is drying in the next step, begin performing Steps 3-20 on the opposite side front wheel speed sensor.

 

Apply (spray) two thin coats of the specified rust penetrating lubricant (corrosion inhibitor) listed in this bulletin, to the complete sensor mounting surface on the bearing hub. Allow to dry for 3-5 minutes between coats.

When the corrosion inhibitor is dry to the touch (about 10 minutes), apply a light coating of the specified grease to the complete sensor mounting surface on the bearing hub and to the sensor and O-ring.

Remove the temporary plug from the hole in the bearing hub.

Install the wheel speed sensor in the bearing hub and install the bolt. Ensure that the sensor is seated flat against the hub.

Tighten

Tighten the wheel speed sensor mounting bolt to 18 N·m (13 lb ft).

 

Disconnect the front wheel speed sensor connector and place a digital volt meter (DVM) across the terminals of the wheel speed sensor connector. Rotate the bearing at approximately one revolution per second. The minimum reading should be at least 350 ACmVs. If the reading is less than 350 ACmVs, the wheel speed sensor must be replaced. Follow Steps 12-15 for instructions on replacing the wheel speed sensor. This step must be repeated after the new sensor has been installed.

Notice: Whenever the brake rotor has been separated from the wheel bearing flange, clean any rust or foreign material from the mating surface of the rotor and flange. Failure to do this may result in increased lateral runout of the rotor and brake.

 

Important: If the rotor was removed using the jack screw method, you must ensure that the hub flange is free of nicks or marks caused by this procedure. Remove all raised nicks or marks before installing the rotor.

 

Align the rotor to its original position on the hub and install the rotor.

Install the caliper and caliper mounting bracket assembly.

Perform the following procedure before installing the brake caliper bracket mounting bolts.

27.1. Remove all traces of the original adhesive patch.

 

27.2. Clean the threads of the bolt with brake parts cleaner, or the equivalent, and allow to dry.

 

27.3. Apply threadlocker to the threads of the bolts.

 

Install the caliper bracket mounting bolts.

Tighten the brake caliper mounting bracket mounting bolts to the specification listed below.

 

Tighten

 

• 1500 Series vehicles -- 175 N·m (129 lb ft)

 

• 2500 Series vehicles -- 300 N·m (221 lb ft)

 

Install the front tire and wheel assembly.

Tighten

Tighten the wheel nuts to 190 N·m (140 lb ft).

 

Complete Steps 21-30 on the opposite side front wheel speed sensor.

Lower the vehicle.

With the engine OFF, gradually apply the brake pedal to approximately 2/3 of its travel distance.

Slowly release the brake pedal.

Wait 15 seconds and repeat Steps 32-33 until a firm pedal is obtained. This will properly seat the brake caliper pistons and brake pads.

Customer Reimbursement - For Canada

Customer requests for reimbursement of previously paid repairs to correct the condition addressed in this bulletin are to be submitted by January 31, 2006.

 

All reasonable customer paid receipts should be considered for reimbursement. The amount to be reimbursed will be limited to the amount the repair would have cost if completed by an authorized General Motors dealer.

 

When a customer requests reimbursement, they must provide the following:

 

• Proof of ownership at time of repair.

 

• Original paid receipt confirming the amount of repair expense(s) that were not reimbursed, a description of the repair, and the person or entity performing the repair.

 

Claims for customer reimbursement on previously paid repairs are to be submitted as required by WINS.

 

Important: Refer to the GM Service Policies and Procedures Manual, section 1.6.2, for specific procedures regarding customer reimbursement verification.

 

Courtesy Transportation

The General Motors Courtesy Transportation program is intended to minimize customer inconvenience when a vehicle requires a repair that is covered by the New Vehicle Limited Warranty. The availability of courtesy transportation to customers whose vehicles are within the warranty coverage period and involved in a product recall is very important in maintaining customer satisfaction. Dealers are to ensure that these customers understand that shuttle service or some other form of courtesy transportation is available and will be provided at no charge. Dealers should refer to the General Motors Service Policies and Procedures Manual for Courtesy Transportation guidelines.

 

Claim Information

Submit a Product Recall Claim with the information indicated below:

 

Repair Performed

Part Count

Part No.

Parts Allow

CC-FC

Labour Op

Labour Hours

Net Item

 

Inspect Wheel Speed Sensor (Inc. Cleaning)

0

N/A

N/A

MA-96

V1256

0.8*

***

 

Add: Vehicles with 8-lug nut wheels

0.1

 

Inspect & Replace One or Both Wheel Speed Sensor (Inc. Cleaning)

1-2

--

**

MA-96

V1257

0.9*

***

 

Add: Vehicles with 8-Lug Nut Wheels

0.1

 

Courtesy Transportation

N/A

N/A

N/A

MA-96

****

N/A

*****

 

Customer Reimbursement (Canadian & Export Dealers/US CAC)

N/A

N/A

N/A

MA-96

V1258

0.2

******

 

* -- For Recall Administrative Allowance, add 0.1 hours to the "Labour Hours".

 

** -- The "Parts Allowance" should be the sum total of the current GMSPO Dealer net price plus applicable Mark-Up for the front wheel speed sensor needed to complete the repair.

 

*** -- The amount identified in the "Net Item" column should represent the sum total of the current GMSPO Dealer net price plus applicable Mark-Up for the actual cost of lubricants needed to perform the required repairs, not to exceed $0.68.

 

**** -- Submit courtesy transportation using normal labor operations for courtesy transportation as indicated in the GM Service Policies and Procedures Manual.

 

***** -- The amount identified in the "Net Item" column should represent the actual dollar amount for courtesy transportation.

 

****** -- The amount identified in the "Net Item" column should represent the dollar amount reimbursed to the customer.

 

 

Refer to the General Motors WINS Claims Processing Manual for details on Product Recall Claim Submission.

 

Customer Notification

General Motors will notify customers of this recall on their vehicle (see copy of customer letter included with this bulletin).

 

Dealer Recall Responsibility -- All

All unsold new vehicles in dealers' possession and subject to this recall MUST be held and inspected/repaired per the service procedure of this recall bulletin BEFORE customers take possession of these vehicles.

 

Dealers are to service all vehicles subject to this recall at no charge to customers, regardless of mileage, age of vehicle, or ownership, from this time forward.

 

Customers who have recently purchased vehicles sold from your vehicle inventory, and for which there is no customer information indicated on the dealer listing, are to be contacted by the dealer. Arrangements are to be made to make the required correction according to the instructions contained in this bulletin. A copy of the customer letter is provided in this bulletin for your use in contacting customers. Recall follow-up cards should not be used for this purpose, since the customer may not as yet have received the notification letter.

 

In summary, whenever a vehicle subject to this recall enters your vehicle inventory, or is in your dealership for service in the future, please take the steps necessary to be sure the recall correction has been made before selling or releasing the vehicle.

 

January 2005

Dear General Motors Customer:

 

General Motors has decided that a defect which relates to motor vehicle safety exists in certain 1999-2002 Chevrolet Silverado, 2000-2002 Chevrolet Tahoe, Suburban, 2002 Chevrolet Avalanche, 1999-2002 GMC Sierra, 2000-2002 GMC Yukon, Yukon XL vehicles located in Ontario, Quebec, Newfoundland, New Brunswick, Nova Scotia, and Prince Edward Island. These vehicles may have a condition permitting corrosion to occur between the front hub/bearing assembly and the wheel speed sensor. If the brakes are applied while the vehicle is travelling at a speed of greater than 6 km/h (3.7 mph) but less than 16 km/h (10 mph), the corrosion may cause an unwanted anti-lock brake system (ABS) activation. If this condition occurred where stopping distance is limited, a crash could occur.

 

Your dealer will clean and treat the affected area, and in some cases, replace the front wheel speed sensor. This service will be performed for you at no charge.

 

You may be contacted by a dealer other than the dealer who sold or is currently servicing your vehicle. Please be advised that you may take your vehicle to the General Motors dealership of your choice to have the recall service work completed. Please contact your dealer as soon as possible to arrange a service date.

 

If parts are required, ask your dealer for details regarding their availability. If parts are not in stock, they can be ordered before scheduling your service date.

 

This letter identifies your vehicle. Presentation of this letter to your dealer will assist their Service personnel in completing the necessary correction to your vehicle in the shortest possible time.

 

If you have already paid for some or all of the cost to replace the front wheel speed sensor(s) due to corrosion, and you have not received reimbursement under a Vehicle Service Contract, you should contact your dealer to seek reimbursement. Please provide your dealer with your original paid receipts or invoices verifying the repair, the amount charged, proof of payment, the date of payment of those charges, and proof of ownership of the vehicle at the time of the repair. Your request for reimbursement, including the information and documents mentioned above, must be received by your dealer by January 31, 2006. Reimbursement may be limited to the amount the repair would have cost if completed by an authorized General Motors dealer.

 

We are sorry to cause you this inconvenience; however, we have taken this action in the interest of your safety and continued satisfaction with our products.

 

Customer Support Department

 

General Motors of Canada Limited

 

04094

[Jackson]

my '99 NBS Sierra does the same thing occasionally. I just haven't taken the time to clean the sensors yet.

 

a pencil eraser is the best from what I've heard.

[davecyr]

Document ID# 1587153

2001 Chevrolet Chevy K Silverado - 4WD

--------------------------------------------------------------------------------

Subject: Product Safety - Front Wheel Speed Sensor Corrosion #04094 - (01/25/2005)

 

 

Thank you very much! Probably more coincidental than something I did then.