P0723
DTC P0723
Circuit Description
The automatic transmission output speed sensor (OSS) provides vehicle speed information to the transmission control module (TCM). The OSS is a permanent magnet generator mounted to the transmission case. The OSS produces an AC voltage as the transmission speed sensor rotor teeth pass through the magnetic field of the sensor. The AC voltage level increases as the speed of the vehicle increases. The TCM converts the AC voltage into a digital signal. The TCM uses the vehicle speed signal to determine shift timing, torque converter clutch (TCC) apply, TCC release, and gear ratio calculations.
When the TCM detects a loss of vehicle speed while the vehicle is in motion, then DTC P0723 sets. DTC P0723 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 ISS DTCs P0716 or P0717.
^ No 1-2 SS electrical DTC P0974.
^ The engine is running for 5 seconds.
^ The transmission range is not in PARK or NEUTRAL.
^ The output speed is 1,000 RPM or more for 2 seconds.
^ An increase in output speed of 500 RPM or greater has not occurred for greater than 2 seconds.
^ The engine torque is greater than 50 N.m (37 lb ft).
^ The ISS has not changed by 500 RPM or more for 2 seconds.
^ The time since the last range change is 6 seconds or more.
Conditions for Setting the DTC
Output speed drops greater than 1,200 RPM for 3.25 seconds.
Action Taken When the DTC Sets
^ The TCM illuminates 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 output speed from input speed, engine speed, and commanded gear.
^ 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 TCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
^ 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 OSS to produce an AC voltage. This step also verifies the integrity of the wiring to the TCM.
4. This step tests the OSS circuit for correct resistance.
Step 1 - Step 6:
Step 7 - Step 13:
