P0723
DTC P0722 or P0723
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provide an overview of each diagnostic category.
DTC Descriptors
DTC P0722
- Output Speed Sensor (OSS) Circuit Low Voltage
DTC P0723
- Output Speed Sensor (OSS) Circuit Intermittent
Diagnostic Fault Information
* DTC P0722 detects a very low vehicle speed signal when the vehicle has a large engine speed in a drive range, constant fault.
* DTC P0723 detects a large unrealistic drop in the vehicle speed signal in a very short period of time, intermittent fault.
Typical Scan Tool Data
Circuit/System Description
The OSS system is a pulse generator consisting of a speed sensor assembly, located in the case extension, and a toothed output speed sensor (OSS) reluctor wheel, which is pressed onto the final drive carrier assembly. As the vehicle drives forward, the OSS reluctor wheel rotates. This rotation produces a variable AC signal in the pick-up coil that is proportional to vehicle speed. The transmission control module (TCM) uses this signal in order to calculate vehicle speed, shift timing, and gear ratios.
Conditions for Running the DTC
P0722
* No ISS DTC P0716 or P0717.
* No OSS DTC P0723.
* No TPS DTC P0120, P0121, P0122, P0123, P0220, P0221, P0222, P0223, P0225, P0226, P0227, P0228, P1120, P1121, P1122, P1125, P1280, P1281, P1282, P1283, P1285, P1286, P1287 or P1288.
* Ignition voltage is between 8.0 and 18.0 volts.
* The transmission is not in PARK or NEUTRAL.
* The engine speed is greater than 500 RPM for 5 seconds.
* The engine torque is greater than 50 N.m (37 lb ft).
* The calc. throttle position is 8 percent or greater.
* The input shaft speed is greater than 1,500 RPM.
* The torque converter clutch (TCC) slip speed is -20 RPM or greater.
* The transmission fluid temperature (TFT) is -40°C (-40°F) or greater.
P0723
* No ISS DTC P0716 or P0717.
* No 1-2 SS electrical DTC P0974.
* Ignition voltage is between 8.0 and 18.0 volts.
* The transmission is not in PARK or NEUTRAL.
* The engine speed is greater than 500 RPM for 5 seconds.
* The engine torque is greater than 50 N.m (37 lb ft).
* The time since the last gear selector range change is 6 seconds or greater.
* The output speed is 350 RPM or greater for 2 seconds.
* No transmission OSS rise 175 RPM or greater to 2 seconds.
* The ISS changes 500 RPM or less for 2 seconds.
Conditions for Setting the DTC
P0722
The output shaft speed is 50 RPM or less for 4.5 seconds.
P0723
The output shaft speed drops greater than 420 RPM for 3.25 seconds.
Action Taken When the DTC Sets
* DTC P0722 and P0723 are type B DTCs.
* The TCM commands maximum line pressure.
* The TCM freezes transmission adaptive functions.
* The TCM calculates vehicle speed based on engine speed and gear ratio.
Conditions for Clearing the DTC
DTC P0722 and P0723 are type B DTCs.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views
Description and Operation Reference
Transmission General Description (Transmission General Description)
Electrical Information Reference
* Circuit Testing
* Connector Repairs
* Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Special Tools
J 35616 GM-Approved Terminal Test Kit
Circuit/System Verification
1. Raise and support the drive wheels.
2. Start and idle the engine.
3. Place the transmission in DRIVE.
4. Monitor Transmission OSS on the scan tool.
5. The Transmission OSS on the scan tool should be greater than 70 RPM.
6. Increase throttle position. The OSS RPM, and OSS AC voltage should steadily increase.
7. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
Important: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
1. Ignition OFF, disconnect the TCM connector.
2. Using the J 35616 GM terminal test kit, connect the DMM between the OSS high signal circuit, TCM connector terminal 41, and the OSS low signal circuit, TCM connector terminal 16. Measure the resistance between the OSS high signal circuit and the OSS low signal circuit. The resistance should be between 1,650 and 3,180 ohms.
• If the value is greater than 3,180 ohms, test the OSS high signal circuit and the OSS low signal circuit for an open. If both circuits test good, replace the OSS.
• If the value is less than 1,650 ohms, test the OSS high signal and the OSS low signal circuits for a shorted together condition. If both circuits test good, replace the OSS.
3. Measure the resistance of the OSS high signal circuit, TCM connector terminal 41, to ground. The resistance should be greater than 10K ohms.
• If the value is less than 10K ohms, disconnect the OSS, test the OSS high signal and the OSS low signal circuits for a short to ground. If both circuits test good, replace the OSS.
4. Connect the TCM connector. Disconnect the OSS connector. Ignition ON, measure the DC voltage between the OSS high signal circuit, OSS connector pin B, and the OSS low signal circuit, OSS connector pin A, to ground. The voltage should be between 2.0 and 3.0 volts DC.
• If the value is greater than 3.0 volts DC, test the affected circuit for a short to voltage. If the value is less than 2.0 volts, replace the PCM.
5. If all circuits/connections test normal, test the OSS.
Component Testing
1. Verify the OSS resistance is between 1,650 and 3,180 ohms.
• If the resistance is not within the specified range, replace the OSS.
2. Using the J 35616 GM terminal test kit, connect the DMM between the OSS high signal, OSS connector pin B, and the OSS low signal circuits, OSS connector pin A, at the OSS connector. Raise and support the drive wheels. While rotating the drive wheels by hand, ensure the AC voltage reading on the DMM is greater than 0.4 volt.
• If the AC voltage is not greater than 0.4 volt, replace the OSS.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
* Vehicle Speed Sensor Replacement (Service and Repair) for OSS replacement
* Control Module References for TCM replacement, setup, and programming.