DTC 24

DTC 24 Circuit Diagram:

DTC 24 Vehicle Speed Sensor:

CIRCUIT DESCRIPTION:

Vehicle speed information is provide to the ECM by the vehicle speed sensor, which alternately grounds the WHT wire located in the meter when the drive wheel are turning. this pulsing action takes place 4096 time per mile, and the ECM will calculate vehicle speed based on the time between pulses.

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

1. Code 24 will set if vehicle speed equals 0 mph when:

^ Engine speed is between 2400 and 4400 rpm.
^ TPS angle is at 0%.
^ Low speed condition (low MAP voltage, high manifold vacuum)
^ Not in Park or Neutral (A/T).
^ All conditions met simultaneously for 5 seconds.
These conditions are met during a road load deceleration. Disregard Code 24 that sets when drive wheels are not turning.

DIAGNOSTIC AIDS:

Scan should indicate a vehicle speed whenever the drive wheels are turning greater than 3 mph. Check the WHT wire for proper connection to be sure they are clean and tight and the harness is routed correctly.
Intermittant Check Procedure

Use a Scan tool and check for proper signal while in drive.