Vehicle Speed Sensor Backup Circuit

Code 42 Description:

Circuit Description
The 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 engine control module. The engine control module determines the vehicle speed based on the frequency of these pulse signals.

Code 42 Diagnostic Chart:

Diagnostic Chart

Code 42 Circuit Diagram:

Circuit Diagram

Code 42 Inspection Procedure:

Inspection Procedure