Ok, hope this helps. The VSS ontrols the Speedometer.
Vehicle speed sensor (VSS) - This may also be known as an output speed sensor (OSS). This sensor sends a varying frequency signal to the TCU to determine the current speed of the vehicle. The TCU uses this information to determine when a gear change should take place based in the various operating parameters.
Turbine speed sensor (TSS) - This may also be known as an input speed sensor (ISS). This sensor sends a varying frequency signal to the TCU to determine the current rotational speed of the input shaft or torque converter. The TCU uses the input shaft speed to determine slippage across the torque converter and potentially to determine the rate of slippage across the bands and clutches. This information is vital to regulate the application of the torque converter lock-up clutch smoothly and effectively.
Sunday, July 31st, 2011 AT 1:15 AM