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 VoltageDTC P0723: Output Speed Sensor (OSS) Circuit Intermittent
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
OSS High Signal | P0722, P0723 | P0722, P0723 | P0722, P0723 | P0722, P0723 |
OSS Low Signal | -- | P0722, P0723 | -- | P0722, P0723 |
Typical Scan Tool Data
Circuit | Short to Ground | Open/High Resistance | Short to Voltage |
|---|---|---|---|
Operating Conditions: Drive vehicle, normal operating temperature Parameter Normal Range: 100-7,000 RPM | |||
Transmission OSS | 0 RPM | 0 RPM | 0 RPM |
Circuit/System Description
The OSS system is a pulse generator consisting of a speed sensor assembly, located in the case extension, and a toothed vehicle speed sensor (VSS) reluctor wheel, which is pressed onto the final drive carrier assembly. As the vehicle drives forward, the VSS 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
DTC P0722
| • | No ISS DTC P0716 or P0717. |
| • | The engine speed is greater than 500 RPM for 5 seconds. |
| • | The engine torque is greater than 50 N·m (37 lb ft). |
| • | The transmission range is not PARK or NEUTRAL. |
| • | No TP sensor DTC P0120 or P0220. |
| • | No OSS DTC P0723. |
| • | The calc. throttle position is 8 percent or greater. |
| • | The input shaft speed is 1,500-5,000 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. |
DTC P0723
| • | No ISS DTC P0716 or P0717. |
| • | The engine speed is greater than 500 RPM for 5 seconds. |
| • | The engine torque is greater than 50 N·m (37 lb ft). |
| • | The transmission range is not PARK or NEUTRAL. |
| • | No 1-2 SS electrical DTC P0974. |
| • | 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
DTC P0722
The output shaft speed is 70 RPM or less for 4.5 seconds.
DTC P0723
The output shaft speed drops greater than 420 RPM for 3.25 seconds.
Action Taken When the DTC Sets
| • | DTCs P0722 and P0723 are type B DTCs. |
| • | The TCM commands maximum line pressure. |
| • | The TCM freezes transmission adaptive functions. |
| • | The TCM calculates input 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
Connector End View Reference
Electrical Information Reference
Scan Tool Reference
DTC Type Reference
Special Tools Required
J 35616 GM Terminal Test Kit
Circuit/System Verification
- Raise and support the drive wheels.
- Start and idle the engine.
- Place the transmission in DRIVE.
- Monitor Transmission OSS on the scan tool.
- The Transmission OSS on the scan tool should be greater than 70 RPM.
Circuit/System Testing
- With the drive wheels supported, the engine running, and the transmission in DRIVE, ensure the Transmission OSS parameter on the scan tool is greater than 70 RPM.
- 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.
- Measure the resistance of the OSS high signal circuit to ground. The resistance should be greater than 10K ohms.
- Measure the resistance between the ISS low signal circuit and ground. The resistance should be greater than 10K ohms.
- Connect the TCM connector. Disconnect the OSS connector. Ignition ON, test the ISS high signal circuit for a short to voltage.
- If all circuits/connections test normal, test or replace the OSS.
| ⇒ | If the value is less than 100 RPM, disconnect the TCM connector. Using the J 35616 GM terminal test kit, connect the DMM between the OSS high signal and the OSS low signal circuits. |
| ⇒ | 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 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 the value is less than 10K ohms, repair the short to ground. |
| ⇒ | If the value is less than 10K ohms, repair the short to ground. |
Component Testing
- Verify the OSS resistance is between 1,650 and 3,180 ohms.
- Using the J 35616 GM terminal test kit, connect the DMM between the OSS high signal and the OSS low signal circuits 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 resistance is not within the specified range, replace the OSS. |
| ⇒ | If the AC voltage is not greater than 0.4 volt, replace the OSS. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
Control Module References for TCM replacement, setup, and programming
