Component Inspection

Component Inspection

1. Ignition "OFF".
2. Disconnect the wheel speed sensor harness connector.
3. Connect resistance (approx. 100 Ohms) to the wheel speed sensor signal circuit.
4. Measure waveform of the wheel speed sensor signal harness while turning the wheel.
A. Specification : High : Approx. 1.4V, Low : Approx. 0.7V (In case that 100 Ohms resistance is used)

CAUTION:
Voltage of the waveform can be calculated by using following expression.
Voltage = Resistance • Current (High : 1.4mA, Low : 0.7mA).




5. Is the measured waveform within specifications and no missing signal?
YES
1) Fault is intermittent caused by faulty HECU, wheel speed sensor or external noise, an interference between harnesses, was repaired and HECU memory was not cleared. Go to "Verification of Vehicle Repair" procedure.
2) If OK, Substitute with a known-good HECU and check for proper operation. If problem is corrected, replace HECU and then go to "Verification of Vehicle Repair" procedure.
NO
1) Check for improper installation of wheel speed sensor. If NG, repair as necessary and then go to "Verification of vehicle Repair" procedure.
2) Check for damage of rotor teeth or wheel bearing. If NG, repair as necessary and then go to "Verification of vehicle Repair" procedure.
3) Substitute with a known-good Wheel speed sensor and check for proper operation. If problem is corrected, replace Wheel speed sensor and then go to "Verification of Vehicle Repair" procedure.