2010 Cadillac Truck Escalade/ESV RWD V8-6.2L Page 2273
* When the vehicle is moving in a forward direction, sensor A detects a particular tooth before sensor B.
* When the vehicle is moving in a reverse direction, sensor B detects a particular tooth before sensor A.
The electronics in the sensor combine the two signals and send a signal with a different pulse width. This signal is interpreted by the TCM for speed
and direction and is transmitted through the data communication circuits to the engine control module (ECM) and the hybrid powertrain control
module. The ECM, hybrid powertrain control module, and transmission control module compare the OSS signal with the ABS wheel speed sensor
signal.
Conditions for Running the DTC
P0721
The ignition is ON.
P0722
* No OSS DTCs P0721 or P0723.
* The selected range is not PARK or NEUTRAL.
* The vehicle speed is greater than 16 km/h (10 mph).
P0723
* No Automatic Transmission Output Shaft Speed Sensor DTCs P0721 or P0722.
* The engine run time is greater than 6 seconds.
Conditions for Setting the DTC
P0721
The transmission control module detects an invalid Automatic Transmission Output Shaft Speed Sensor direction.
P0722
* The transmission control module detects no signal from the Automatic Transmission Output Shaft Speed Sensor.
* The transmission output speed is less than 50 RPM for 1.5 seconds.
P0723
* The transmission control module detects an unrealistic signal drop from the Automatic Transmission Output Shaft Speed Sensor.
* Automatic Transmission Output Shaft Speed Sensor DTC P0723 has not failed this ignition.
* The transmission output speed is 1,000 RPM or greater for 6 seconds.
* The transmission output speed drops 1,300 RPM for greater than 4 seconds and does not recover.
Action Taken When the DTC Sets
P0721
The transmission control module calculates vehicle direction.
P0722 and P0723
The transmission control module calculates vehicle speed based on the wheel speed sensors.
Conditions for Clearing the DTC
* P0723 is a Type A DTC.
* P0721 and P0722 are a Type B DTC.
Diagnostic Aids
Inspect the Automatic Transmission Output Shaft Speed Sensor, harness, and connector pins for metallic debris and the hybrid direct, 2-3-4 clutch
housing assembly machined teeth for damage or misalignment. Even one bent or misaligned tooth, and or contact with the Automatic Transmission
Output Shaft Speed Sensor, may cause this DTC to set. Proper torque of 9-13 Nm (80-115 lb in) to the Automatic Transmission Output Shaft
Speed Sensor mounting bolt is critical to proper Automatic Transmission Output Shaft Speed Sensor operation. The hybrid system is very sensitive
to the Automatic Transmission Output Shaft Speed Sensor signal for overall operation.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Diagrams)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
