Component Location
General Description
The wheel speed sensor is the essential component the ABS ECU uses to calculate vehicle speed and to determine whether wheel lock occurs. For example, rear wheel speed signal is used as a referecnce value, for vehicle speed, in front wheel drive vehicles, and if a difference between front and rear wheel speed occurs, then ABS control is performed. Wheel speed sensor is active hall-sensor type and good at temperature and noise chariteristic. Digital wave is produced as tone wheel rotate according as hall sensor principle. Frequency of duty wave is changed in proportion to rotation of tone wheel and HECU calculate vehicle speed by this frequency.
DTC Description
The ABS ECU monitors the wheel speed sensor signal continuously. This code is set if when the ABS control cycle is continued abnormally. Warning lamp is turned OFF if the detected fault is not more than when the IG KEY is turned to ON again, and wheel speeds are more than 12 Km/h.
DTC Detecting Condition
Item | Detecting Condition | Possible cause |
Case1 | DTC Strategy | ? ABS continuous control monitoring | ? Improper installation of wheel speed sensor ? Abnormal Rotor and wheel bearing |
Monitoring Period | ? Continuous |
Enable conditions | ? Continuous ABS and EBD control for a time period >= 60s at one or more wheels |
Fail Safe | ? ABS is switched off immediately. ? The ABS and the EBD warning lamps are activated. ? Continuous ABS and EBD control of the appropriate wheel(s). The wheel may not have sufficient braking capacity. |
Case2 | DTC Strategy | ? Wheel Speed difference monitoring |
Monitoring Period | ? Continuous |
Enable conditions | ?Max. wheel speed difference is chosen as bellow 1. (FL wheel speed - RL wheel speed) 2. (FR wheel speed - RR wheel speed) 3. (FL wheel speed - FR wheel speed) - 1.1m/s (Approx.4km/h) 4. (RL wheel speed - RR wheel speed) -1.1m/s (Approx. 4km/h) ? Vehicle < 100Km/h If wheel speed difference is contrinued as bellow, fault is detected. 1. 1.7m/s (Approx.6km/h) = Max.wheel speed diff.< 3.3m/s (Approx. 12km/h) for 18sec 2. 3.3m/s (Approx.12km/h) = Max. wheel speed diff. for 9sec ? Vehicle > 100Km/h If wheel speed difference is contrinued as bellow, fault is detected 1. (6% * vehicle speed) = Max.wheel speed diff.< (12% * vehicle speed) for 18sec 2. (12%*vehicle speed) = Max. wheel speed diff. for 9 sec ? Spinning wheel, decelerating wheel 1. If any wheel is doing a shows strong deceleration (e.g. caused by hand brake) the fault detection filter time is set to 18s. 2. If any spinning wheel is detected the fault detection filter time is set to 72s. |
Fail Safe | ? If the location can not be determined, a general tone wheel fault is stored. (At the time of detection no wheel speed is at Vmin.) In this case: ABS and EBD is shut off immediately. ? ABS and EBD control of a faulty wheel is not longer possible. ? The ABS and the EBD warning lamps are activated. |
Schematic Diagram