Mazda B-Series 1998-06

4-Wheel Anti-Lock Brake System (ABS)

Print

This system is used on the Navajo, 1996-98 MPV,and 1995-98 B Series Pick-up models with 4WD and the 4.0L engine.

The 4WABS system consists of the following components:

  1. The anti-lock Hydraulic Control Unit (HCU)
  2.  
  3. 4WABS electronic control module
  4.  
  5. The front wheel speed sensors-located on the steering knuckles
  6.  

  1. The rear speed sensor-located on the rear axle housing.
  2.  
  3. The front speed sensor tone rings
  4.  
  5. The rear speed sensor tone rings
  6.  
  7. The G-switch
  8.  
  9. The ABS main system and pump motor relays
  10.  

ABS Hydraulic Unit



Removal & Installation


Click image to see an enlarged view

Fig. Front end of the 4-wheel ABS system

  1. Disconnect the battery ground cable.
  2.  
  3. Unplug the 8-pin connector from the unit, and the 4-pin connector from the pump motor.
  4.  
  5. Disconnect the 5 inlet and outlet tubes from the unit. Immediately plug the ports.
  6.  
  7. Remove the 3 unit attaching nuts and lift out the unit.
  8.  
  9. Installation is the reverse of removal. Torque the mounting nuts to 12-18 ft. lbs. and the tube fittings to 10-18 ft. lbs.
  10.  

After reconnecting the battery, it may take 10 miles or more of driving for the Powertrain Control Module to relearn its driveability codes.

  1. Bleed the brakes.
  2.  

Testing
Pump Testing
  1. Disconnect the HCU pump motor electrical plug.
  2.  
  3. Connect a Digital Volt/Ohm Meter (DVOM) across the two pump terminals and record the reading.
  4.  
  5. The reading should be between 52-68 Ohms
  6.  
  7. If not, replace the pump motor.
  8.  

Description & Operation



The anti-lock control system consists of the following components:



Hydraulic control unit (HCU)
 
Anti-lock brake control module
 
Rear anti-lock brake sensor
 
Rear anti-lock brake sensor indicator
 
Front anti-lock brake sensor
 
Front anti-lock brake sensor indicator
 
Yellow ABS warning indicator
 
Red brake warning indicator
 

The anti-lock brake control module manages anti-lock braking. When the ignition switch is placed in the RUN position, the module carries out a preliminary electrical check. At approximately 20 km/h (12 mph), the hydraulic pump motor is turned on for approximately 0.5 second. Any malfunction of the ABS disables the ABS and the anti-lock brake warning indicator illuminates. However, the power-assist braking system still functions normally.

The ABS module needs to be reconfigured whenever a new ABS module is installed. Follow the WDS or equivalent Tester directions for the configuration procedure.

The electronic brake distribution force controls the rear brake pressure and acts as an electronic proportioning valve. It is controlled by the ABS module. When the electronic brake force distribution is disabled, the amber ABS warning indicator illuminates.

Using a specially developed pressure/pedal movement mechanism, the panic assist braking functions by fully applying the brakes during a panic stop. Depending on the vehicle speed, if a pedal stroke is more rapid than normal, the brake booster automatically applies full brake boost. Panic assist is disabled when the driver releases the brake pedal.

Diagnosis & Testing



System Self-Test

The 4WABS module performs system tests and self-tests during startup and normal operation. The valve, sensor and fluid level circuits are monitored for proper operation. If a fault is found, the 4WABS will be deactivated and the amber ANTI LOCK light will be lit until the ignition is turned OFF. When the light is lit, the Diagnostic Trouble Code (DTC) may be obtained. Under normal operation, the light will stay on for about 2 seconds while the ignition switch is in the ON position and will go out shortly after.

The Diagnostic Trouble Codes (DTC) are an alphanumeric code and a scan tool, such as the Special Service Tool NGS (New Generation Star) Tester 49-T088-0A0, is required to retrieve the codes. The DTC code chart has been included.



Click image to see an enlarged view

Fig. 4-Wheel Anti-lock Brake System (4WABS) diagnostic trouble code chart-Navajo



Click image to see an enlarged view

Fig. 4-Wheel Anti-lock Brake System (4WABS) diagnostic trouble code chart-1995-97 B Series Pick-up



Click image to see an enlarged view

Fig. 4-Wheel Anti-lock Brake System (4WABS) diagnostic trouble code chart-1998 B Series Pick-up



Click image to see an enlarged view

Fig. 4-Wheel Anti-lock Brake System (4WABS) diagnostic trouble code chart-1996-98 MPV

Electronic Brake Control Module



Removal & Installation
  1. Disconnect the battery ground cable.
  2.  
  3. Unplug the wiring from the ECU.
  4.  
  5. Remove the mounting bolts, slide the ECU off its bracket.
  6.  
  7. Installation is the reverse of removal. Torque the mounting screw to 5-6 ft. lbs. and the connector bolt to 4-5 ft. lbs.
  8.  

After reconnecting the battery, it may take 10 miles or more of driving for the Powertrain Control Module to relearn its driveability codes.

Speed Sensor Rings



Removal & Installation
Front
2-Wheel Drive


Click image to see an enlarged view

Fig. Front wheel sensor ring-4-wheel ABS/rear wheel drive

  1. Raise and support the front end on jackstands.
  2.  
  3. Remove the wheels.
  4.  
  5. Remove the caliper, rotor and hub.
  6.  
  7. Using a 3-jawed puller, remove the ring from the hub. The ring cannot be reused; it must be replaced.
  8.  

To install:

  1. Support the hub in a press so that the lug studs do not rest on the work surface.
  2.  
  3. Position the new sensor ring on the hub. Using a cylindrical adapter 98mm ID X 106mm OD, press the ring into place. The ring must be fully seated!
  4.  
  5. The remainder of installation is the reverse of removal.
  6.  

4-Wheel Drive

The front speed sensor ring is an integral component of the wheel hub/bearing assembly. If the speed sensor ring requires service for any reason, the wheel hub/bearing assembly must be replaced.

Rear

On Navajo and B Series Pick-up models, the ring is located on the differential case inside the axle housing. Once it is pressed off the case it cannot be reused. This job should be left to a qualified service technician as it requires the rear differential to be disassembled.

Wheel Speed Sensors



Front Wheel Speed Sensors
Removal & Installation


Click image to see an enlarged view

Fig. Front wheel speed sensor components

  1. Inside the engine compartment, disconnect the sensor from the harness.
  2.  
  3. Unclip the sensor cable from the brake hose clips.
  4.  
  5. Remove the retaining bolt from the spindle and slide the sensor from its hole.
  6.  
  7. Installation is the reverse of removal. Tighten the retaining bolt to 40-60 inch lbs. (5-7 Nm) for Navajo/B Series Pick-up and 14-18 ft. lbs. (19-25 Nm) for the MPV.
  8.  

Testing
  1. Disconnect the speed sensor wire harness plug from the sensor or sensor pigtail.
  2.  
  3. Connect a Digital Volt/Ohm Meter (DVOM) across the two sensor terminals and record the reading.
  4.  
  5. The reading should be within the following ranges for the appropiate model and sensor.

    B Series Pick-up-1.0-1.4k Ohms
     
    Navajo-0.270-0.330k Ohms
     
    MPV-1.4-1.8k Ohms
     

  6.  

Rear Wheel Speed Sensors
Removal & Installation
Navajo And B Series Pick-Up


Click image to see an enlarged view

Fig. Rear wheel speed sensor-4-wheel ABS

  1. Disconnect the wiring from the harness.
  2.  
  3. Remove the sensor hold-down bolt and remove the sensor from the axle.
  4.  

To install:

  1. Thoroughly clean the mounting surfaces. Make sure no dirt falls into the axle. Clean the magnetized sensor pole piece. Metal particles can cause sensor problems. Replace the O-ring.
  2.  
  3. Coat the new O-ring with clean engine oil.
  4.  
  5. Position the new sensor on the axle. It should slide into place easily. Correct installation will allow a gap of 0.005-0.045 in.
  6.  
  7. Torque the hold-down bolt to 25-30 ft. lbs. (34-41 Nm).
  8.  
  9. Connect the wiring.
  10.  

Testing
Navajo And B Series Pick-Up
  1. Remove the rear wheel speed sensor from the axle housing.
  2.  
  3. Connect a Digital Volt/Ohm Meter (DVOM) across the two sensor terminals and record the reading.
  4.  
  5. The reading should be between 0.9 and 2.5k Ohms.
  6.  
  7. If not, replace the sensor.
  8.  

 
label.common.footer.alt.autozoneLogo