GM 19302667 Sensor Asm,Vehicle Speed

There are various electric-shift transfer cases on the models covered, along with several combinations of speed sensors available. The Vehicle Speed Sensor (VSS) transmits information to the PCM for the driveability program and is positioned at the rear output shaft. The process for checking and replacing the output shaft speed sensor is similar to that of the VSS. A scan tool is necessary to access speed sensor data and trouble codes. It is important to always use a new O-ring when installing the VSS, and the O-ring should be lubricated with DEXRON VI (or equivalent) transmission fluid prior to installation.

To remove the vehicle speed sensor (VVS), raise the vehicle and place it securely on jack stands. Then, disconnect the electrical connector. On 2WD models, remove the VSS hold-down bolt and the VSS. Remove the old O-ring from the VSS and discard it, and be sure to use a new O-ring when installing the VSS . The installation is the reverse of the removal steps.

Various engine sensors and components have checking procedures,the engine coolant temperature (ECT) sensor is a thermistor that changes resistance with temperature, and a failure in the circuit can cause trouble codes. The resistance should be measured when cold and warm while ensuring reference voltage from PCM is around 5.0 volts for the verification. Manifold Absolute Pressure (MAP) Sensor monitors changes in intake manifold pressure then varies its voltage output accordingly. Look at the reference voltage and signal voltage with the ignition on and engine off, and observe voltage changes as the engine's vacuum changes. Intake Air Temperature (IAT) Sensor acts as a thermistor where you can measure its resistance at different temperatures to make sure it changes as expected. Also, use a scan tool to monitor the IAT sensor for performance. The oxygen sensor in exhaust detects oxygen content which you can check its millivolt signal while warming up your engine. Check whether the oxygen sensor heater has correct voltage or not. Vehicle Speed Sensor (VSS) provides speed data to PCM which can be checked for reference voltage. Depending on the type of engine, Camshaft Sensor and Crankshaft Sensor should be checked for resistance and proper signal output. Finally, Knock Sensors detect engine knock which should be checked for reference voltage and resistance. If any component fails these checks, replacement may be necessary.

The Vehicle Speed Sensor (VSS) is a permanent magnet generator mounted on the transmission. It is triggered by a toothed rotor on the transmission output shaft. As the output shaft rotates, the sensor produces an AC voltage, the frequency of which is proportional to vehicle speed. The PCM uses the sensor input signal for several different engine, transmission and radio control functions. The VSS signal also drives the speedometer on the instrument panel. A defective VSS can cause various driveabilily and transmission problems. To replace it, raise the vehicle and support it securely on jackstands. Disconnect the electrical connector from the VSS, which is located on the right side of the extension housing on automatic transmission models and on the left side of the extension housing on manual transmissions. Remove the mounting bolt and withdraw the VSS from the transmission case. Replace the sensor O-ring and lubricate it with clean transmission fluid. Installation is the reverse of removal.

A toothed rotor on the transmission output shaft causes the Vehicle Speed Sensor (VSS), which is a permanent magnet generator mounted on the transmission, to produce an AC voltage. The ECM/PCM uses this signal for different engine and transmission control functions as well as driving the speedometer on the instrument panel. Driveability and transmission problems can result from a defective VSS. To check the VSS operation, raise the vehicle and locate the sensor. Check for any looseness or breaks in terminals and wires and repair if necessary. Back probe the two wire terminals of the VSS connector and connect a voltmeter set on AC volts scale. With ignition key ON, engine OFF, rotate one rear tire while monitoring voltmeter. As minimum as 0.5 volts should be produced by the sensor with increasing speed of rotation of transmission output shaft. Turn off ignition key and disconnect electrical connector from sensor. Measure resistance across two terminals using ohmmeter, which should be approximately 1,000 to 3,000 ohms at 68 degrees F.Temperature If test results are incorrect replace VSS.Replacing means raising vehicle, disconnecting electrical connector, removing mounting bolt then drawing VSS from transmission case.Replace sensor O-ring.Then reinstall VSS back following opposite steps used during removal.

There are a variety of electric-shift transfer cases on the models covered and several different combinations of speed sensors are available. The Vehicle Speed Sensor (VSS) sends information to the PCM for the driveability program and is located at the rear output shaft. The procedure for checking and replacement of the output shaft speed sensor is essentially the same as the procedure for the Vehicle Speed Sensor (VSS). A scan tool must be used to access speed sensor data and trouble codes.

There are a variety of electric-shift transfer cases on the models covered and several different combinations of speed sensors are available. The Vehicle Speed Sensor (VSS) sends information to the PCM for the driveability program and is located at the rear output shaft. The procedure for checking and replacement of the output shaft speed sensor is essentially the same as the procedure for the Vehicle Speed Sensor (VSS). A scan tool must be used to access speed sensor data and trouble codes.

There are three speed sensors on the transfer case, the first is located at the front output shaft, the second at the rear output shaft, and the third, the Vehicle Speed Sensor, which also sends inputs to the Powertrain Control Module (PCM) and is situated at the rear output shaft. All three sensors are variable reluctance type sensors that generate an AC voltage signal; as speed increases, both the AC voltage and the number of pulses rise proportionately with the sensor's rotation. The process for checking and replacing the transfer case output shaft speed sensors is similar to that of the Vehicle Speed Sensor.

The Vehicle Speed Sensor (VSS) is a permanent magnet generator mounted on the transmission. It is triggered by a toothed rotor on the transmission output shaft. As the output shaft rotates, the sensor produces an AC voltage, the frequency of which is proportional to vehicle speed. The PCM uses the sensor input signal for several different engine, transmission and radio control functions. The VSS signal also drives the speedometer on the instrument panel. A defective VSS can cause various driveability and transmission problems. To replace it, raise the vehicle and support it securely on jackstands. Disconnect the electrical connector from the VSS. Remove the mounting bolt and withdraw the VSS from the transmission case. Replace the sensor O-ring and lubricate it with clean transmission fluid. Installation is the reverse of removal.

First, disconnect the electrical connector and remove the sensor mounting bolt. Then, remove the VSS mounting bolt and take out the VSS from the transmission. If it's difficult to remove, wiggle it from side-to-side while pulling it out.

Use jackstands to securely support the vehicle after raising it.

The oxygen sensor in the exhaust monitors oxygen content. To check it, you can check its millivolt signal while the engine warms up. It is also important to inspect the oxygen sensor heater and ensure it receives proper voltage.

The VSS signal drives the speedometer on the instrument panel.

The VSS is located at the rear output shaft.

The manifold absolute pressure (MAP) sensor monitors intake manifold pressure changes and varies its voltage output accordingly. To check it, you should check the reference voltage and signal voltage with the ignition on and engine off, and observe voltage changes as the engine's vacuum changes.

The intake air temperature (IAT) sensor acts as a thermistor. To check it, you can measure its resistance at different temperatures to ensure it changes as expected. Additionally, you should monitor the IAT sensor using a scan tool to verify its performance.

A scan tool is required to access speed sensor data and trouble codes.

This manual covers models with various electric-shift transfer cases and different combinations of speed sensors.