For 1990-2009 cars

### 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 provides an overview of each diagnostic category.

### DTC Descriptors

DTC P0722: Output Speed Sensor (OSS) Circuit Low Voltage
DTC P0723: Output Speed Sensor (OSS) Intermittent

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Output Speed Sensor Supply Voltage | P0722, P0723 | P0722, P0723 | P0722, P0723 | P0723
Output Speed Sensor Signal | P0722, P0723 | P0722, P0723 | P0722, P0723 | P0723

### Typical Scan Tool Data

#### Input Speed Sensor (ISS) Signal

Circuit | Normal Range | Short to Ground | Open/High Resistance | Short to Voltage
--- | --- | --- | --- | ---
Operating Conditions: Engine running, normal operating temperature
Input Speed Sensor Signal | 0-7,000 RPM | 0 RPM | 0 RPM | 0 RPM
Input and Output Shaft Speed Sensor Supply Voltage | -- | 0 RPM | 0 RPM | 0 RPM
8.3-9.3V = OK Any other voltage = Out of range

#### ISS/OSS Supply Voltage

Circuit | Normal Range | Short to Ground | Open/High Resistance | Short to Voltage
--- | --- | --- | --- | ---
Operating Conditions: Key ON, Engine OFF or Engine running, normal operating temperature
Input Speed Sensor Signal | Operational | Operational | Operational | Operational
Input and Output Shaft Speed Sensor Supply Voltage | Operational | Out of range | Out of range | Out of range
8.3-9.3 V = OK Any other voltage = Out of range

### Circuit/System Description

The output speed sensor (OSS) is a hall-effect type sensor. The OSS mounts to the control valve upper body assembly and connects to the control solenoid (w/body and TCM) valve assembly through a wire harness and connector. The sensor faces the output shaft machined teeth surface. The sensor receives 8.3-9.3 volts on the input/output speed sensor (ISS/OSS) supply voltage circuit from the transmission control module (TCM). As the output shaft rotates, the sensor produces a signal frequency based on the machined surface of the output shaft. This signal is transmitted through the OSS signal circuit to the TCM. The TCM uses the OSS signal to determine line pressure, transmission shift patterns, torque converter clutch (TCC) slip speed and gear ratio.

### Conditions for Running the DTC

#### P0722

• | Start the ignition voltage, run the engine.

• | The engine torque is between 50 and 1,492 N·m (37 and 1,100 lb ft).

• | DTC P0716, P0717, P0723 are not set.

• | TFT exceed 0°C (32°F).

• | The selected range is not PARK or NEUTRAL.

• | The transmission input speed is between 1,000-6,500 RPM.

• | The engine speed is between 3,200 and 5,000 RPM.

• | The calculated throttle position is greater than 8 percent.

#### P0723

• | DTC P0723 is not set.

• | No ISS DTC P0716 or P0717.

• | No OSS DTC P0722.

• | Run the engine, start the ignition voltage.

• | Greater than 6 seconds since last range change.

### Conditions for Setting the DTC

#### P0722

The transmission output speed is less than or equal to 70 RPM for 4.5 seconds.

#### P0723

• | Transmission input speed varies is less than 500 RPM for 2 seconds.

• | Transmission output speed varies is between 0-500 RPM for 2 seconds.

• | The transmission output speed is 1,000 RPM or greater for 2 seconds.

• | The transmission output speed drops 1,200 RPM for greater than 1.5 seconds and does not recover.

### Action Taken When the DTC Sets

• | The TCM freezes transmission adaptive functions.

• | The TCM turns OFF all solenoids.

### Conditions for Clearing the DIC/DTC

DTCs P0722 and P0723 are Type A DTCs.

### Diagnostic Aids

Inspect the OSS, harness, connector and control solenoid (w/body and TCM) valve assembly pins for metallic debris and output shaft machined face for damage or misalignment. Proper torque of the OSS mounting bolt is critical to proper OSS operation. Use the J 35616 GM-approved terminal test kit for any test that requires probing the control solenoid (w/body and TCM) valve assembly harness connector or a component harness connector.

### Reference Information

#### Schematic Reference

Automatic Transmission Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### DTC Type Reference

• | Diagnostic Trouble Code (DTC) Type Definitions

• | Diagnostic Trouble Code (DTC) List/Type

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

• | Scan Tool Output Controls

• | Scan Tool Data List

• | Scan Tool Data Definitions

#### Special Tools

J 35616 GM-Approved Terminal Test Kit

### Circuit/System Verification

Operate the vehicle at 16-32 km/h (10-20 mph) while observing the transmission OSS on the scan tool. The transmission OSS should vary with the vehicle speed and not drop out.

### Circuit/System Testing

1. Turn the ignition ON.
2. Observe the transmission ISS/OSS supply voltage circuit status on the scan tool. The parameter should display OK.

⇒ | If the parameter does not display OK, disconnect the ISS/OSS connector from the control solenoid (w/body and TCM) valve assembly and recheck the scan tool display.

⇒ | If the transmission ISS/OSS supply voltage circuit status still displays OK, visually inspect the OSS, harness, connector, the control solenoid (w/body and TCM) valve assembly pins for metallic debris and output shaft machined surface for damage or misalignment.

⇒ | Repair or replace the damaged components.

3. Perform the Control Solenoid Valve and Transmission Control Module Assembly Input Shaft Speed/Output Shaft Speed Input Test.

⇒ | The scan tool Transmission OSS parameter should display 100-400 RPM.

⇒ | If the Transmission OSS parameter is between 100-400 RPM, replace the ISS/OSS assembly.

⇒ | If no OSS RPM is displayed or the parameter is out of range, replace the control solenoid (w/body and TCM) valve assembly.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Input and Output Speed Sensor Replacement

• | Control Solenoid Valve and Transmission Control Module Assembly Inspection

• | Control Solenoid Valve and Transmission Control Module Assembly Input Shaft Speed/Output Shaft Speed Input Test

• | Service Fast Learn Adapts

• | Control Module References for TCM replacement, setup, and programming