Automatic Transmission - 4L80-E/4L85-E
DTC P0722 or P0723
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides 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
Circuit/System Description
The OSS is a pulse generator consisting of a speed sensor assembly, located in the case extension, and a toothed reluctor wheel, which is pressed onto the final drive carrier assembly. As the vehicle drives forward, the reluctor wheel rotates. This rotation produces a variable AC signal in the pick-up coil of the OSS 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
* DTC P0121, P0122, P0123, P0716, P0717, P0722, P0723, P1810, P1815, P1816, or P1818 is not set.
* The ignition voltage is between 8 and 18-volts.
* The engine speed is between 500 and 6,500 RPM for 5 seconds.
* The transmission is not in PARK or NEUTRAL.
* Power take-off (PTO) is not active.
* The throttle position (TP) sensor is 10 percent or greater.
* The transmission ISS is 1,500-6,500 RPM.
* The transmission temperature is greater than -40°C (-40°F).
* The torque converter clutch (TCC) slip speed is greater -20 RPM.
* The engine torque is between 50-882 Nm (37-650 lb ft).
P0723
* DTC P0716, P0717, or P0974 is not set.
* The ignition voltage is between 8 and 18-volts.
* The engine speed is between 500 and 6,500 RPM for 5 seconds.
* The transmission range selector has not changed for at least 6 seconds.
* The 4WD range selector has not changed for at least 6 seconds.
* The transmission input shaft speed has not changed by 300 RPM or greater for at least 2 seconds.
* The transmission output shaft speed is greater than 1,000 RPM for 2 seconds.
* The transmission output shaft speed has not changed by 500 RPM or greater for at least 2 seconds.
Conditions for Setting the DTC
P0722
The transmission output shaft speed is 200 RPM or less for 4.5 seconds.
P0723
The transmission output shaft speed drops greater than 1,200 RPM for 3 seconds.
Action Taken When the DTC Sets
DTC P0722 and P0723 are type B DTCs.
Conditions for Clearing the DTC
DTC P0722 and P0723 are type B DTCs.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics (Diesel) (Electrical Diagrams)Automatic Transmission Controls Schematics (Gas) (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Transmission General Description (Transmission General Description)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Special Tools
* J 35616 GM Terminal Test Kit
* J 44152 Jumper Harness (20 Pins)
Circuit/System Verification
1. Monitor OSS parameter on the scan tool. The OSS parameter should increase as the drive wheel speed increases.
2. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records List.
Circuit/System Testing
1. Ignition OFF, disconnect the TCM X1 connector.
2. Measure for 1,260-1,911 ohms between the OSS high signal circuit terminal 41 and the OSS low signal circuit terminal 16.
• If greater than the specified range, test the OSS high signal and the OSS low signal circuits for an open/high resistance. If the circuits/connections test normal, replace the input speed sensor (ISS).
• If less than 820 ohms, test the OSS high signal and the OSS low signal circuits for a shorted together condition. If the circuits/connections test normal, replace the ISS.
3. Measure for greater than 10 ohms of resistance between the OSS high signal circuit terminal 41 and ground.
• If less than the specified range, repair the short to ground.
4. Measure for greater than 10 ohms of resistance between the OSS low signal circuit terminal 16 and ground.
• If less than the specified range, repair the short to ground.
5. Connect the TCM connector. Disconnect the transmission 20-way connector.
6. Ignition ON, test the OSS high signal circuit terminal 41 for a short to voltage.
• If all circuits test normal, test or replace the internal transmission wiring harness or the OSS.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the repair.
Vehicle Output Speed Sensor Replacement (Vehicle Output Speed Sensor Replacement).
Control Module References (Programming and Relearning) for TCM replacement, setup, and programming.