P0723
DTC P0723
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 TCM uses this signal in order to calculate vehicle speed, shift timing and gear ratios.
If the TCM detects a large change in vehicle speed in a short period of time, then DTC P0723 sets. DTC P00723 is a type B DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0723 Output Speed Sensor Circuit Intermittent
Conditions for Running the DTC
^ No TP DTC P0120 or P0220.
^ No ISS DTC P0716 or P0717.
^ No 1-2 SS electrical DTC P0974.
^ The engine speed is greater than 500 RPM for 5 seconds.
^ The transmission range is not in PARK or NEUTRAL.
^ The engine torque is greater than 50 Nm (37 ft. lbs.).
^ The time since the last gear selector range change is 6 seconds or more.
^ The output speed is 350 RPM or greater with no rise greater than 175 RPM for 2 seconds.
^ The change in ISS is not greater than 500 RPM for 2 seconds.
Conditions for Setting the DTC
The output shaft speed drops greater than 420 RPM for 3.25 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 input speed, engine speed and gear ratio for shift timing.
^ 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 P0723 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 trip in which the TCM does not send an 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:
