Diagnostic Instructions
DTC Descriptors
DTC P2160: Vehicle Speed Sensor (VSS) 2 Circuit Low Voltage
DTC P2161: Vehicle Speed Sensor (VSS) 2 Circuit Intermittent
Diagnostic Fault Information
Circuit
| Short to Ground
| Open/High Resistance
| Short to Voltage
| Signal Performance
|
VSS Supply Voltage
| P2160, P2161
| P2160, P2161
| P2160, P2161
| P2161
|
VSS Signal
| P2160, P2161
| P2160, P2161
| P2160, P2161
| P2161
|
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. |
| • | 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 N·m (44 lb ft) and less than 8192 N·m (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 and 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 475 RPM or greater. |
| • | Output speed signal is decreasing: current transfer case speed signal - last valid output speed 255 RPM or less. |
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
| • | 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. |
Reference Information
Schematic Reference
Connector End View Reference
Component Connector End Views
Description and Operation
Transfer Case Description and Operation
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Raise and support the drive wheels.
- Start and idle the engine.
- Place the transmission in DRIVE.
- Monitor VSS on the scan tool under engine data.
- The VSS on the scan tool should be greater than 100 RPM.
Circuit/System Testing
- Measure the resistance between the VSS high signal circuit and the VSS low signal circuit. The resistance should be between 1,420-2,140 ohms.
| ⇒ | If the value is greater than 2,140 ohms, test the VSS high signal circuit and the VSS low signal circuit for an open. |
| ⇒ | If the value is less than 1,420 ohms, test the VSS high signal and the VSS low signal circuits for a shorted together condition. |
- Measure the resistance of the VSS high signal circuit to ground. The resistance should be greater than 10M ohms.
| ⇒ | If the value is less than 10M ohms, repair the short to ground. |
- Measure the resistance between the VSS low signal circuit and ground. The resistance should be greater than 10M ohms.
| ⇒ | If the value is less than 10M ohms, repair the short to ground. |
- Reconnect the ECM connector. Disconnect the VSS connector. Ignition ON, test the VSS high signal circuit for a short to voltage.
| ⇒ | If all circuits/connections test normal, test or replace the VSS. |
- If all previous steps for circuit checking and VSS replacement have been made and all component testing has been performed and the condition persists replace the ECM.
Component Testing
- Verify the VSS resistance is within the specified range.
- Using a terminal test kit, connect the DMM between the VSS high signal and the VSS low signal circuits at the VSS connector. Raise and support the drive wheels. While rotating the drive wheels by hand ensure the AC voltage reading on the DMM is above
0.4 volt.
| ⇒ | If the AC voltage is not above 0.4 volt, replace the VSS. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Ensure that the VSS is 500 RPM or greater for 3 seconds and does not change more than 500 RPM or greater for 3 seconds. |
