DTC 42

DTC 42 No.1 Vehicle Speed Sensor Signal Circuit



HINT: In test mode, diagnostic trouble code 42 is output when vehicle speed is 5 km/h (3mph) or below. This is not abnormal.

CIRCUIT DESCRIPTION






The No.1 vehicle speed sensor outputs a 4-pulse signal for every revolution of the rotor shaft, which is rotated by the transmission output shaft via the driven gear. After this 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 these pulse signals.

INSPECTION USING AN OSCILLOSCOPE



- Waveform between terminals SPD and EI when vehicle speed is approx. 20 km/h (12 mph).
- The greater the vehicle speed, the greater the number of No.1 vehicle speed sensor signals produced.


WIRING DIAGRAM





INSPECTION PROCEDURE