Hyundai Accent: Brake System (ABS/ESC) / ABS(Anti-Lock Brake System)

Description and Operation ➤

Components and Components Location

- Components

1. ABS Control Module (HECU)
2. Front Wheel Speed Sensor
3. Rear Wheel Speed Sensor
4. ABS Warning lamp
5. EBD / Parking brake warning lamp

Schematic Diagrams ➤

Repair procedures

- Inspection ABS System Bleeding This procedure should be followed to ensure adequate bleeding of air and filling of the ESC unit, brake lines and master cylinder with brake fluid.

1.Remove the reservoir cap and fill the brake reservoir with brake fluid.

• If there is any brake fluid on any painted surface, wash it off immediately.

• When pressure bleeding, do not depress the brake pedal.

• Recommended fluid........ DOT3 or DOT4

2.Connect a clear plastic tube to the wheel cylinder bleeder plug and insert the other end of the tube into a half filled clear plastic bottle.

3.Connect the GDS to the data link connector located underneath the dash panel.

4.Select and operate according to the instructions on the GDS screen

• You must obey the maximum operating time of the ESC motor with the GDS to prevent the motor pump from burning.

1)Select vehicle name.

2) Select ABS/ESC system.

3)Select HCU air bleeding mode.

5.Pump the brake pedal several times, and then loosen the bleeder screw until fluid starts to run out without bubbles. Then close the bleeder screw (A).[Front]

6.Repeat the procedure for wheel in the sequence shown below until air bubbles no longer appear in the fluid.

7.Refill the master cylinder reservoir to MAX (upper) level line.

Troubleshooting ➤

ABS Control Module

- Components

1. Front - right tube
2. Rear - left tube
3. Rear - right tube
4. Front - left tube
5. MC SEC
6. MC PRI
7. ABS control module (HECU)
8. Bracket

1.Turn the ignition switch OFF and then disconnect the negative (-) battery cable.

2.Pull up the lock of the HECU connector, then disconnect the connector.

3.Remove the brake fluid from the master cylinder reservoir with a syringe.

• Be sure to completely remove foreign substances from around brake fluid reservoir and cap before opening the reservoir cap. If not, it may cause contamination of brake fluid and deterioration in braking performance.

• Do not spill brake fluid on the vehicle, it may damage the paint; if brake fluid does contact the paint, wash it off immediately with water.

4.Disconnect the brake tubes from the HECU by unlocking the nuts counterclockwise with a spanner.

Tightening torque : 13.7 - 16.7 N.m (1.4 - 1.7 kgf.m, 10.1 - 12.3 lb-ft)

5.Loosen the HECU bracket bolts (A), then remove HECU and bracket.

Tightening torque :16.7 - 25.5 N.m (1.7 - 2.6 kgf.m, 12.3 - 18.8 lb-ft)

6.Remove the 3 bolts, then remove the bracket from HECU.

Tightening torque :7.8 - 9.8 N.m (0.8 - 1.0 kgf.m, 5.8 - 7.2 lb-ft)

1.To install, reverse the removal procedure.

2.Tighten the HECU mounting bolts and nuts to the specified torque.

3.After installation, bleed the brake system. (Refer to ABS System - "ABS System Bleeding")

Front Wheel Speed Sensor

- Components

1. Front wheel speed sensor
2. Front wheel speed sensor cable

1.Loosen the wheel nuts slightly.Raise the vehicle, and make sure it is securely supported.

2.Remove the front wheel and tire (A) from the front hub.

Tightening torque :107.9 - 127.5 N.m (11.0 - 13.0 kgf.m, 79.6 - 94.0 lb-ft)

• Be careful not to damage the hub bolts when removing the front wheel and tire.

3.Loosen the mounting holt and then remove the wheel speed sensor cable from the strut assembly.

Tightening torque :7.8 - 11.8 N.m (0.8 - 1.2 kgf.m, 5.8 - 8.7 lb-ft)

4.Remove the wheel speed sensor cable braket bolt (A).

Tightening torque : 7.8 - 11.8 N.m (0.8 - 1.2 kgf.m, 5.8 - 8.7 lb-ft)

5.Loosen the bolt and then remove the wheel speed sensor (A).

Tightening torque :7.8 - 11.8 N.m (0.8 - 1.2 kgf.m, 5.8 - 8.7 lb-ft)

6.Remove the front wheel guard.(Refer to Body - "Front Wheel Guard")

7.Disconnect the wheel speed sensor connector (A) and then remove it.

8.To install, reverse the removal procedure.

1.Measure the output voltage between the terminal of the wheel speed sensor and the body ground.

• In order to protect the wheel speed sensor, when measuring output voltage, a 100Ω resister must be used as shown.

2.Compare the change of the output voltage of the wheel speed sensor to the normal change of the output voltage as shown below.

V_low : 0.59V - 0.84VV_high : 1.18V - 1.68VFrequency range : 1 - 2,500 Hz

Rear Wheel Speed Sensor

- Components

[Drum Type]

1. Front wheel speed sensor
2. Front wheel speed sensor cable

[Disc Type]

1. Front wheel speed sensor
2. Front wheel speed sensor cable

1.Loosen the wheel nuts slightly.Raise the vehicle, and make sure it is securely supported.

2.Remove the rear wheel and tire (A) from front hub.

Tightening torque :107.9 - 127.5 N.m (11.0 - 13.0 kgf.m, 79.6 - 94.0 lb-ft)

• Be careful not to damage the hub bolts when removing the rear wheel and tire.

3.Disconnect the rear wheel speed sensor connector.

4.Loosen the screws and then remove the brake disc.

Tightening torque :4.9 - 5.9 N.m (0.5 - 0.6 kgf.m, 3.6 - 4.3 lb-ft)

5.Loosen the bolts and then remove the hub bearing.

Tightening torque :49.0 - 58.8 N.m (5.0 - 6.0 kgf.m, 36.2 - 43.4 lb-ft)

6.To install, reverse the removal procedure.

1.Loosen the wheel nuts slightly.Raise the vehicle, and make sure it is securely supported.

2.Remove the rear wheel and tire (A) from front hub.

Tightening torque :107.9 - 127.5 N.m (11.0 - 13.0 kgf.m, 79.6 - 94.0 lb-ft)

• Be careful not to damage the hub bolts when removing the rear wheel and tire.

3.Loosen the screw and then remove the drum.

Tightening torque :4.9 - 5.9 N.m (0.5 - 0.6 kgf.m, 3.6 - 4.3 lb-ft)

4.Disconnect the rear wheel speed sensor connector.

5.Loosen the hub mounting bolts (A) and then remove the hub from the torsion beam.

Tightening torque :44.1 - 53.9 N.m (4.5 - 5.5 kgf.m, 32.9 - 39.8 lb-ft)

6.To install, reverse the removal procedure.

1.Measure the output voltage between the terminal of the wheel speed sensor and the body ground.

• In order to protect the wheel speed sensor, when measuring output voltage, a 100Ω resister must be used as shown.

2.Compare the change of the output voltage of the wheel speed sensor to the normal change of the output voltage as shown below.

V_low : 0.59V - 0.84VV_high : 1.18V - 1.68VFrequency range : 1 - 2,500 Hz