P0722
DTC P0722
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 low output speed and the vehicle has a large engine speed in a drive gear, 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 MAP DTCs P0107 or P0108.
^ No TP DTCs P0120 or P0220.
^ No ISS DTCs P0716 or P0717.
^ No OSS DTC P0723.
^ The engine is running for 5 seconds.
^ The transmission range is not PARK or NEUTRAL.
^ The Calc. Throttle Position is 8 percent or more.
^ The input speed is between 1,500 RPM and 5,000 RPM.
^ The engine torque is greater than 50 N.m (37 lb ft).
^ The TFT is -40°C (-40°F) or more.
^ The TCC slip speed is -20 RPM or more.
Conditions for Setting the DTC
The transmission OSS is less than 200 RPM for 4.5 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 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 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:
