With 2 Wheel Drive

Code 24 Vehicle Speed Sensor Circuit Fault (2WD):

Wiring Diaghram For Code 24 Vehicle Speed Sensor Circuit Fault (2WD):

CODE 24 - VSS CIRCUIT FAULT


CIRCUIT DESCRIPTION:

The output sensor circuit consist of a magnetic induction type sensor, digital radio adapter, located in the instrument panel and wiring. Gear teeth cut in the outside diameter of the rear internal gear induce and alternating cluster in the sensor. On two wheel drive vehicles, this current is transmitted to an instrument cluster where it is passed on to the PCM. The digital radio adapter compensates for various axil ratios and converts the signal to a square wave for use by the speedometer, cruise control, and anti-lock brake system. Code 24 will set if range selected or indicated is not Park or Neutral. Input speed is at least 3000 rpm. Output rpm is at least 200 for at least 1 second. If the input speed sensor is not operational at start up, this can cause the vehicle speed sensor to read zero.




TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.

1. Test one verifies a vehicle speed sensor voltage at the PCM.

2. Test two directly verifies the operation of the vehicle speed sensor.

3. Test three checks CKT's 821 and 822 up to the instrument cluster.



DIAGNOSTIC AIDS:

Check all connections especially those at the transmission pass-thru connector. If the input speed sensor is not functioning at start up, it will cause the vehicle speed sensor to read zero.
While Code 24 is set, the "SCAN TOOL" will display an rpm derived from input speed.