Vehicle Speed Sensor Check VINs T and V

Fig. 046 - WIRING DIAGRAM for Vehicle Speed Sensor Check. VIN T, VIN V:

VEHICLE SPEED SENSOR CHECK (VSS)- DIGITAL CLUSTER

Vehicle speed is sensed by a Vehicle Speed Sensor located behind the I.P. cluster. The VSS is supplied with 12 volts from ignition and ECM. The output from the VSS to the ECM is a "toggling" of the voltage. As the speedometer turns, the 12V signal from the ECM is turned "ON" and "OFF". The faster the vehicle speed the more rapidly the signal toggles. This VSS input into the ECM is used to calculate amount of EGR and also TCC engagement.
The VSS will turn "ON" a CEL only if the ECM does not see a VSS signal for at least 26 seconds under an MVS load of from 25%-50%. The CEL will go "OFF" as load falls below 25%. The light will come back "ON" if load exceeds 25% again for at least 10 seconds. Thus, a VSS generated CEL is load sensitive and will go "ON" and "OFF" with load.

Fig. 045 - Chart For Vehicle Speed Sensor Check.:

1. Checks for a VSS signal. Normally voltage will vary from under 1 volt to over 10 volts as wheel spins slowly. The faster the wheel is spun the less the variation.
2. Checks for good VSS output signal from ECM. Normal voltage will be above 10 volts if circuit and ECM are OK.

Fig. 044 - WIRING DIAGRAM for Vehicle Speed Sensor Check. VIN T, VIN V:

VEHICLE SPEED SENSOR CHECK (VSS)- EXC. DIGITAL I.P. CLUSTERS

Vehicle speed is sensed by a Vehicle Speed Sensor located behind the I.P. cluster. The VSS is supplied with 12 volts from ignition and the ECM. The output from the VSS to the ECM is a "toggling" of the voltage. As the speedometer turns, the 12V signal from the ECM is turned "ON" and "OFF". The faster the vehicle speed, the more rapidly the signal toggles. This VSS input into the ECM is used to calculate amount of EGR and to control TCC engagement.
The VSS will turn "ON" a CEL only if the ECM does not see a VSS signal for at least 26 seconds under an MVS load of from 25% to 50%. The CEL will go "OFF" as load falls below 25%. The light will come back "ON" if load exceeds 25% again for at least 10 seconds. Thus, a VSS generated CEL is load sensitive and will go "ON" and "OFF" with load.

Fig. 043 - Chart For Vehicle Speed Sensor Check.:

1. Checks for a VSS signal. Normally voltage will vary from under 1 volt to over 10 volts as wheel is turned slowly. The faster the wheel is spun the less the variation.
2. Checks for battery voltage to Terminal "C" of I.P. harness connector.
3. Checks for a good ground at I.P. harness connector.
4. Checks for good VSS output signal from ECM. Normal voltage will be above 10 volts if circuit and ECM is OK.