Diagnostic Fault Information
Circuit/System Description
The vehicle speed sensor (VSS) provides vehicle speed information to the engine control module (ECM). The VSS is a permanent magnet
generator. The sensor is mounted in the transfer case facing the rear internal gear which is splined to the output shaft assembly. As the output shaft
and internal gear rotate, the toothed rotor of the internal gear produces AC voltage as the rotor teeth pass through the magnetic field of the sensor.
The AC voltage level and the number of pulses increase as the speed of the vehicle increases. The ECM converts the voltage to vehicle speed. The
ECM uses the output shaft speed signal to determine shift timing, as well as transfer case range.
Conditions for Running the DTC
P2160
* No input speed sensor (ISS) DTCs P0716 or P0717.
* No output speed sensor (OSS) DTCs P0722 or P0723.
* No vehicle speed sensor (VSS) DTCs P2160 or P2161.
* The throttle position is greater than 5 percent and less than 99 percent.
* The transmission is not in Reverse Inhibit state.
* The transmission is not in PARK or NEUTRAL.
* The transmission is not performing garage shifting.
* No engine torque, throttle position, and turbine speed DTCs.
* The engine torque is greater than 60 Nm (44 lb ft) and less than 8192 Nm (6042 lb ft).
* The input speed is greater than 1000 RPM and less than 7500 RPM.
P2161
* The transmission is not performing garage shifting.
* The transmission is not in Reverse Inhibit state.
* The transmission is not in PARK or NEUTRAL.
* The engine speed is 1000 RPM or greater.
* No crank sensor or P2160 DTCs.
Conditions for Setting the DTC
P2160
* No speed signal from the transfer case speed sensor.
* The transfer case output shaft speed is 50 RPM or less.
P2161
* Loss of speed signal from the transfer case speed sensor.
* Output speed signal is increasing: current transfer case speed signal - last valid output speed greater than 475 RPM.
* Output speed signal is decreasing: current transfer case speed signal - last valid output speed less than 255 RPM.
Action Taken When the DTC Sets
* DTCs P2160 and P2161 are Type B DTCs.
* The TCM commands maximum line pressure.
* The TCM freezes transmission adaptive functions.
* The TCM calculates vehicle speed from the automatic transmission input shaft speed sensor and commanded gear.
Conditions for Clearing the DTC
DTCs P2160 and P2161 are Type B DTCs.
Diagnostic Aids
* The transfer case drain plug provides a good ground point.
* The EL-49742 - harness provides a good source for 12 V and ground.
* Inspect the rear internal gear teeth for damage.
* Visually inspect the VSS for cracks or damage.
* Ensure the VSS is properly torqued to the transfer case housing.
* This diagnostic relates to the VSS located in the transfer case and not the OSS located within the transmission.
