GM Cadillac Deville_Fleetwood_ELD_Seville 1990-1998

General Information

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The Anti-lock Brake System (ABS) is an electronically operated, all wheel brake control system. Major components include the vacuum power brake booster, master cylinder, the wheel speed sensors, Hydraulic Control Unit (HCU), control module, a relay, and the pressure control valves.

The system is designed to retard wheel lockup during periods of high wheel slip when braking. Retarding wheel lockup is accomplished by modulating fluid pressure to the wheel brake units. When the control module detects a variation in voltage across the wheel speed sensors, the ABS is activated. The control module opens and closes various valves located inside the HCU. These valves, called dump and isolation valves, modulate the hydraulic pressure to the wheels by applying and venting the pressure to the brake fluid circuits.

Teves Mk II





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Fig. Teves Mk II anti-lock brake system component locations-1990 Eldorado and Seville



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Fig. Teves Mk II anti-lock brake system component locations-1990 Deville and Fleetwood

The Teves Mk II Anti-lock Brake System (ABS) is only used on all 1990 vehicles. The 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. The Teves Mk II system components include a Electronic Brake Control Module (EBCM), a separate control relay, hydraulic control unit (HCU), and 4 wheel speed sensors (one at each wheel).

Teves Mk IV





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Fig. Teves Mk IV ABS component locations-1991-93 Deville and Fleetwood

The Teves Mk IV anti-lock brake system is used on 1991-93 Deville and Fleetwood. Some vehicles are equipped with a Traction Control System (TCS) in addition to ABS. The TCS prevents the wheels from spinning excessively during acceleration or when turning corners at higher speeds. The TCS also prevents wheel slip on slippery surfaces, allowing improved acceleration ability and vehicle stability. The ABS and TCS are both part of the same hydraulic and electrical system. Both systems use many of the same components; a problem in either system usually will disable the other system until it is repaired.

The Teves Mk IV system components include a Electronic Brake Control Module (EBCM), a pressure modulator valve (also know as the Hydraulic control unit-HCU), and 4 wheel speed sensors-one on each wheel.

BOSCH ANTI-LOCK BRAKE SYSTEM





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Fig. Bosch® anti-lock brake system component locations-1991-92 Eldorado and Seville; 1993-98 vehicles similar

The Bosch® Anti-lock Brake System (ABS) is used on 1991-98 Eldorado and Seville, and 1994-98 Deville. Some vehicles are equipped with a Traction Control System (TCS) in addition to ABS. The TCS prevents the wheels from spinning excessively during acceleration or when turning corners at higher speeds. The TCS also prevents wheel slip on slippery surfaces, allowing improved acceleration ability and vehicle stability. The ABS and TCS are both part of the same hydraulic and electrical system. Both systems use many of the same components; a problem in either system usually will disable the other system until it is repaired.

The Bosch® system components include a Electronic Brake Control Module (EBCM) on non-TCS vehicles or the Electronic Brake and Traction Control Module (EBTCM) on TCS equipped vehicles, a hydraulic modulator (also know as the Hydraulic control unit-HCU), and 4 wheel speed sensors- one on each wheel.

precautions





Certain components within the ABS system are not intended to be serviced or repaired individually.
 
Do not use rubber hoses or other parts not specifically specified for and ABS system. When using repair kits, replace all parts included in the kit. Partial or incorrect repair may lead to functional problems and require the replacement of components.
 
Lubricate rubber parts with clean, fresh brake fluid to ease assembly. Do not use shop air to clean parts; damage to rubber components may result.
 
Use only DOT 3 brake fluid from an unopened container.
 
If any hydraulic component or line is removed or replaced, it may be necessary to bleed the entire system.
 
A clean repair area is essential. Always clean the reservoir and cap thoroughly before removing the cap. The slightest amount of dirt in the fluid may plug an orifice and impair the system function. Perform repairs after components have been thoroughly cleaned; use only denatured alcohol to clean components. Do not allow ABS components to come into contact with any substance containing mineral oil; this includes used shop rags.
 
The Anti-Lock control unit is a microprocessor similar to other computer units in the vehicle. Ensure that the ignition switch is OFF before removing or installing controller harnesses. Avoid static electricity discharge at or near the controller.
 
If any arc welding is to be done on the vehicle, the control unit should be unplugged before welding operations begin.
 

 
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