2010 Cadillac Truck Escalade/ESV RWD V8-6.2L Page 2261
6. If all of the above test normal, replace the B14A/B14C ISS/OSS assembly.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Perform the Input and Output Speed Sensor Replacement (See: Powertrain Management/Transmission Control Systems/Sensors and
Switches - Transmission and Drivetrain/Sensors and Switches - A/T/Transmission Speed Sensor/Service and Repair/6L45/6L50/6L80/6L90 -
Automatic Transmission).
* Control solenoid valve assembly - refer to Control Module References (See: Testing and Inspection/Programming and Relearning) for
replacement, setup, and programming.
* Perform the Control Solenoid Valve and Transmission Control Module Assembly Input Shaft Speed/Output Shaft Speed Input Test (See:
Transmission and Drivetrain/Automatic Transmission/Transaxle/Testing and Inspection/Component Tests and General
Diagnostics/6L45/6L50/6L80/6L90 - Automatic Transmission/Control Solenoid Valve and Transmission Control Module Assembly Input
Shaft Speed/Output Shaft Speed Input Test).
* Perform the Service Fast Learn Adapts (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Testing and
Inspection/Programming and Relearning) following all transmission related repairs.
P0721
DTC P0721-P0723
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC P0721
- Output Speed Sensor Performance
DTC P0722
- Output Speed Sensor Circuit Low Voltage
DTC P0723
- Output Speed Sensor Circuit Intermittent
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
The Automatic Transmission Output Shaft Speed Sensor assembly has 2 internal hall-effect type sensors, and is capable of sensing both speed and
direction. The Automatic Transmission Output Shaft Speed Sensor mounts to the A/T rear case assembly and is connected to the control solenoid
valve assembly through a wire harness and connector. The sensor faces the hybrid direct, 2-3-4 clutch housing assembly machined teeth surface.
The sensor receives 8.3-9.3 volts on the OSS supply voltage circuit from the transmission control module. As the output shaft rotates, the sensor
produces a signal frequency based on the machined surface of the output shaft.
The two sensor elements in the Automatic Transmission Output Shaft Speed Sensor assembly are spaced approximately 1/2 a tooth apart.
* When the vehicle is moving in a forward direction, sensor A detects a particular tooth before sensor B.
