Transmission Speed Sensor: Testing and Inspection

NO.1 VEHICLE SPEED SENSOR INSPECTION

No.1 Vehicle Speed Sensor:

(a) Connect the positive (+) lead from battery to terminal 3 and negative (-) lead to terminal 2.
(b) Connect the positive (+) lead from a voltmeter to terminal 1 and negative (-) lead to terminal 2.




(c) Revolve shaft.

(d) Check that there is voltage change from approx. 0.0 Volts to 11.0 Volts or more between terminals 1 and 2.

HINT: The voltage change should be 4 times for every revolution of the speed sensor shaft.

- If operation is not as specified, replace the sensor.


NO.2 VEHICLE SPEED SENSOR INSPECTION
(a) Jack up the one of the rear wheels.




(b) Connect an ohmmeter between the terminals of the No.2 Vehicle Speed Sensor.

(c) Spin the wheel and check that the meter needle deflects from 0.0 Ohms to infinite Ohms.

HINT: This sensor outputs 1 pulse for each 1 revolution of the transmission output shaft.

- If operation is not as specified, replace the sensor.


^ editor's notes ^
- The ECM will normally use the No.2 Vehicle Speed Sensor signal to determine shift points. However, if that signal is not input, the ECM is programmed to automatically switch to the No.1 Vehicle Speed Sensor signal.
- If both speed sensors fail, the transmission will operate only in 1st gear. There will be no upshift.