Dtc P0504 Brake Switch A / B Correlation

In this system, the signals of the duplex type stop light switch (STP and ST1-) are used to judge whether the brake system is abnormal. When signals that indicate depressing and releasing the brake pedal are detected simultaneously, the ECM interprets this as a malfunction of the stop light switch.

Dtc P0500 Vehicle Speed Sensor A

The skid control ECU outputs a signal that is proportional to vehicle speed. This signal is based on the rotation of the ABS wheel speed sensors. After this, the signal is converted into a more precise rectangular waveform by the waveform shaping circuit inside the combination meter. It is then transmitted to the ECM. The ECM determines the vehicle speed based on the frequency of this signal.