P0722
DTC P0722
Circuit Description
The vehicle speed sensor (VSS) system is a pulse generator consisting of a speed sensor assembly, located in the case extension, and a toothed vehicle speed sensor reluctor wheel, which is pressed onto the final drive carrier assembly. As the vehicle drives forward, the vehicle speed sensor reluctor wheel rotates. This rotation produces a variable AC signal in the pickup coil that is proportional to vehicle speed. The transmission control module (TCM) uses this signal in order to calculate vehicle speed, shift timing and gear ratios.
If the TCM detects a low vehicle speed with a high engine speed while in a drive range, then DTC P0722 sets. DTC P0722 is a type B DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0722 Output Speed Sensor Circuit Low Voltage
Conditions for Running the DTC
^ No TP DTC P0120 or P0220.
^ No ISS DTC P0716 or P0717.
^ No VSS DTC P0723.
^ The engine speed is greater than 500 RPM for 5 seconds.
^ No engine torque malfunction.
^ The calc. throttle position is 8 percent or more.
^ The engine torque is greater than 50 Nm (27 ft. lbs.).
^ The input shaft speed is 1,500 - 5,000 RPM.
^ The TCC slip speed is -20 RPM or more.
^ The TFT is -40°C (-40°F) or more.
^ The transmission range is not in PARK or NEUTRAL.
Conditions for Setting the DTC
The output shaft speed is 70 RPM or less for 4.5 seconds.
Action Taken When the DTC Sets
^ The TCM requests the ECM to illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
^ The TCM commands maximum line pressure.
^ The TCM freezes transmission adaptive functions.
^ The TCM calculates vehicle speed from the input speed, engine speed and gear ratio for shift timing.
^ The TCM inhibits Torque management.
^ The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Freeze Frame and Failure Records.
^ The TCM stores DTC P0722 in TCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.
Conditions for Clearing the MIL/DTC
^ The ECM turns OFF the MIL after the third consecutive drive trip in which the TCM does not send a MIL illumination request.
^ A scan tool can clear the MIL/DTC.
^ The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
^ The TCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the TCM.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
3. This step tests the ability of the VSS to produce an AC voltage. This step also verifies the integrity of the wiring to the TCM.
4. This step tests the VSS circuit for correct resistance.
Step 1 - Step 5:
Step 6 - Step 15:
