Anti-Lock: Overview Kia Spectra I

DESCRIPTION

The optional Anti-Lock Brake System (ABS) operates on all wheels. Wheel speed sensors and ABS control unit monitor all 4 wheels and can adjust hydraulic pressure to each wheel, maintaining optimum braking by preventing wheel lock-up. The ABS system consists of 4 wheel speed sensors, rear disc brakes, ABS control unit and a Hydraulic Control Unit (HCU). (Scheme 1)

Scheme 1

If battery voltage is not available to the ABS control unit, or if voltage is less than 10 volts, ABS control unit will not operate. As a result, ABS warning light illuminates. Some initial circuits or components to inspect are as follows

1. Worn or damaged ignition switch.
2. Open ignition wiring to ABS control unit.
3. Low battery voltage (less than 10 volts).
4. Blown ABS fuse (10-amp), located in passenger compartment fuse box.
5. Open in system ground circuit.

ABS control unit has detected either a malfunction of sensor connection, sensor coil or wiring harness to power or ground circuits. Control unit may have also detected an interrupted sensor coil or connection or a defective input trigger circuit at control unit terminals No. 1 and 2. If any of these malfunctions occur, ABS control unit will set this code.

If ABS control unit detects one of the following conditions, this DTC will set. An intermittently interrupted or shorted front wheel speed sensor coil or wiring, a damaged sensor rotor or air gap is too large or too small.

Scheme 2

1. Raise and support vehicle. Remove appropriate front wheel. Using a feeler gauge, check air gap between speed sensor tip and sensor rotor teeth. Clearance should be.028-.059" (.70-1.50 mm). (Scheme 2) If clearance is as specified, go to next step. If clearance is not as specified, replace wheel speed sensor or sensor rotor.
2. Check engine and ignition system wiring for misrouted wires. Wires may cause interference to speed sensor wiring. Check wheel speed sensor wiring for incorrect installation. Check for loose wheel speed sensor mounting and contamination due to brake pad dust in air gap between speed sensor and sensor rotor. Repair or replace components as necessary. If components are okay, go to next step.
3. Check for poor connection, rust and deformation of wheel speed sensor connector. Check for damaged speed sensor wiring. Repair as necessary. If components are okay, go to next step.
4. Ensure ignition switch is in OFF position. Disconnect front wheel speed sensor connector. Using a DVOM, check resistance between wheel speed sensor connector terminals (component side). If resistance is 1.0-1.3 k/ohms, go to next step. If resistance is not 1.0-1.3 k/ohms, replace wheel speed sensor.
5. Check continuity between ground and terminal No. 2 at front wheel speed sensor (component side). See «WIRING DIAGRAMS»(ref-4492-S21919235932000063000000). If continuity exists, replace wheel speed sensor. If continuity does not exist, perform appropriate wheel speed sensor circuit or connection malfunction DTC. See «ABS DIAGNOSTIC TROUBLE CODES (DTC)»(ref-4492-S04422169612000063000000) table.

ABS control unit has detected either a malfunction of sensor connection, sensor coil or wiring harness to power or ground circuits. Control unit may have also detected an interrupted sensor coil or connection or a defective input trigger circuit at control unit terminals No. 19 and 20. If any of these malfunctions occur, ABS control unit will set this code.

ABS control unit has detected either a malfunction of sensor connection, sensor coil or wiring harness to power or ground circuits. Control unit may have also detected an interrupted sensor coil or connection or a defective input trigger circuit at control unit terminals No. 5 and 6. If any of these malfunctions occur, ABS control unit will set this code.

If ABS control unit detects one of the following conditions, this DTC will set. An intermittently interrupted or shorted left rear wheel speed sensor coil or wiring, a damaged sensor rotor or air gap is too large or too small.

ABS control unit has detected either a malfunction of sensor connection, sensor coil or wiring harness to power or ground circuits. Control unit may have also detected an interrupted sensor coil or connection or a defective input trigger circuit at control unit terminals No. 22 and 23. If any of these malfunctions occur, ABS control unit will set this code.