Enhanced Testing

C1245 - Wheel Speed Frequency Error






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. The wheel speed sensor generates sinewave signals, based on magnetic field made by a permanent magnet in the speed sensor, when the tone wheel rotates. The frequency and AC voltage changes in proportion to the wheel speed, and the HECU determines the speed by calculating the frequeny of the signal.

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.


Detecting Condition