P0503

DTC P0500/21 VEHICLE SPEED SENSOR CIRCUIT MALFUNCTION
DTC P0503/23 VEHICLE SPEED SENSOR CIRCUIT MALFUNCTION

CIRCUIT DESCRIPTION

With ABS:




Vehicles, which are equipped with ABS (Anti-Lock Brake System), detect the vehicle speed using the skid control ECU and wheel speed sensor. The wheel speed sensor monitors the wheel rotation speed and sends a signal to the skid control ECU. The skid control ECU converts the wheel speed signal into a 4-pulse signal and transmits it to the ECM via the combination meter. The ECM determines the vehicle speed based on the frequency of the pulse signal.

Without ABS:

DTC Detection Condition:

Vehicles, which are not equipped with ABS, detect the vehicle speed using the No. 1 vehicle speed sensor. The No. 1 vehicle speed sensor transmits a 4-pulse signal for every revolution of the rotor shaft, which is rotated by the transaxle output shaft via the driven gear. The 4-pulse signal is converted into a more precise rectangular waveform by the waveform shaping circuit inside the combination meter. The signal is then transmitted to the ECM. The ECM determines the vehicle speed based on the frequency of the pulse signal.

Wiring Diagram:

Step 1:

Step 2:

INSPECTION PROCEDURE

HINT: Read freeze frame data using a hand-held tester or OBD II scan tool. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data, from the time the malfunction occurred.