Diagnostic Instructions
DTC Descriptors
DTC P0722: Output Speed Sensor (OSS) Circuit Low Voltage
DTC P0723: Output Speed Sensor (OSS) Circuit Intermittent
Diagnostic Fault Information
Circuits
| Short to Ground
| Open/High Resistance
| Short to Voltage
| Signal Performance
|
OSS Low Signal
| --
| P0722, P0723
| --
| --
|
OSS High Signal
| P0722, P0723
| P0722, P0723
| P0722, P0723
| --
|
Circuit/System Description
The output shaft speed (OSS) sensor 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 output shaft sensor 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
| • | DTCs P0121, P0122, P0123, P0716, P0717, or P0723 are not set. |
| • | The ignition voltage is between 8 and 18 volts. |
| • | The engine speed is between 500 and 6,500 RPMs for 5 seconds. |
| • | The transmission is not in PARK or NEUTRAL. |
| • | The TP sensor is 8 percent or greater. |
| • | The transmission input shaft speed is 1,500-6,500 RPM. |
| • | The transmission temperature is greater than -40°C (-40°F). |
| • | The TCC slip speed is greater -20 RPM. |
P0723
| • | DTCs P0716, P0717, or P0974 are not set. |
| • | The ignition voltage is between 8 and 18 volts. |
| • | The engine speed is between 500 and 6,500 RPMs for 5 seconds. |
| • | The transmission is not in PARK or NEUTRAL. |
| • | The transmission input shaft speed has not changed by 500 RPM or greater for at least 2 seconds. |
| • | The transmission output shaft speed is greater than 321 RPM for 2 seconds. |
Conditions for Setting the DTC
P0722
The transmission output shaft speed is 64 RPM or less for 4.5 seconds.
P0723
The transmission output shaft speed drops more than 385 RPM for 3 seconds.
Action Taken When the DTC Sets
P0722 and P0723 are Type B DTCs.
Conditions for Clearing the DTC
P0722 and P0723 are Type B DTCs.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics
Connector End View Reference
Component Connector End Views
Description and operation
Transmission General Description
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References
Special Tools
| • | J 35616
GM-Approved Terminal Test Kit |
Circuit/System Verification
- Monitor OSS parameter on the scan tool. The OSS parameter should increase as the drive wheel speed increases.
- 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
- Ignition OFF, disconnect the TCM X1 connector.
- 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 shaft speed sensor. |
| ⇒ | 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 input shaft speed sensor. |
- Measure for more 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. |
- Measure for more 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. |
- Connect the TCM connector. Disconnect the transmission 20-way connector.
- 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 sensor. |
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the repair.
