Pontiac 24225896 Sensor Assembly, Vehicle Speed

To remove and install the front sensor on 1990 vehicles, disconnect the negative battery cable, detach the sensor connector, and raise the vehicle to remove the wheel and tire assembly. For Eldorado and Seville, disengage the sensor cable grommet from the wheel well, remove the sensor cable from brackets, and take out the sensor mounting bolt to remove the sensor. Inspect the sensor face for contaminants and clean as necessary. For installation, coat the sensor with anti-corrosion compound where it contacts the knuckle, install the sensor with the mounting bolt, and secure the cable in retainers, ensuring it is clear of moving parts. Connect the sensor to the wiring harness, reinstall the wheel and tire assembly, and reconnect the negative battery cable. For 1991 Deville and Fleetwood, follow similar steps, ensuring to cut the strap retaining the sensor cable and tighten the mounting bolt to specified torque. For 1992-93 Deville and Fleetwood, disconnect the negative battery cable, detach the sensor connector, and remove the hub and bearing assembly, cleaning the sensor housing area. Pry the slinger from the speed sensor assembly and carefully remove the speed sensor, inspecting for rust or water intrusion. Apply sealant to the bearing hub, install the sensor using a press, and connect the wiring. For 1991 Eldorado and Seville, follow similar removal and installation steps, ensuring to coat the sensor with anti-corrosion compound and secure the cable. For 1992-98 Eldorado and Seville and 1994-98 Deville, the front wheel speed sensors are integrated with the hub and bearing assembly and must be replaced if separated. For the rear sensor on 1990 Deville and Fleetwood, disconnect the negative battery cable, remove side panel carpeting, detach the sensor connector, and raise the vehicle to disconnect the sensor cable. Remove the sensor and inspect for contaminants. For installation, coat the sensor with anti-corrosion compound, secure the cable, and connect the sensor to the harness. For 1990 Eldorado and Seville, follow similar steps, ensuring to inspect the sensor face. For 1991-93 Fleetwood and Deville, remove the hub and bearing assembly, clean the sensor housing, and inspect for wear before installation. For 1992-98 Eldorado and Seville and 1994-98 Deville, note that the rear wheel speed sensor is integral to the rear hub and bearing assembly and cannot be serviced separately.

The Vehicle Speed Sensor (VSS) informs the Powertrain Control Module (PCM) of vehicle speed and controls the Torque Converter Clutch (TCC). For 1992 and earlier models, the VSS is behind the instrument cluster; for 1993 onwards, it's on the transmission's rear extension. For the former, remove the instrument cluster and then the VSS screw. For the latter, raise the vehicle's rear, disconnect the electrical connector, and remove the retaining bolt to extract the sensor. Installation is the reverse, inspecting the O-ring seal and checking transmission fluid levels.

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.

The 4L60-E and 4L65-E transmissions have their VSS located on the right side of the extension housing. However, both of the 4L80-E and 4L85-E transmissions do not use VSS, instead, they have Input Shaft Speed (ISS) and Output Shaft Speed (OSS) sensors. Disconnecting the cable at its negative battery terminal is important. To prevent rolling and slipping off, put the vehicle on jack stands after lifting it. In case of oil spills while working with the vehicle speed sensor, keep a drain pan beneath it. The electrical connector should be detached from the Vehicle Speed Sensor. For removal of VSS remove the electrical connector as well as sensor mounting bolt. After that remove VSS mounting bolt and extract VSS from transmission. If you want to remove a VSS in this situation, you can grab it tightly then move it back and forth while removing it out of transmission. In case VSS has O-ring, ensure that you check whether it is torn or worn out so that you can replace it if need be. Replace if damaged. When installing a new VSS replace the O-ring even if old one looks fine here. Reinstallation is simply done by reversing what was done during removal process for installation purposes. Therefore, fill up transmission fluid up to required level after inspection process is over.

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.

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.

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.

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.

The Vehicle Speed Sensor (VSS) informs the Powertrain Control Module (PCM) of vehicle speed and controls the Torque Converter Clutch (TCC). For 1992 and earlier models, the VSS is behind the instrument cluster; for 1993 onwards, it's on the transmission's rear extension. For the former, remove the instrument cluster and then the VSS screw. For the latter, raise the vehicle's rear, disconnect the electrical connector, and remove the retaining bolt to extract the sensor. Installation is the reverse, inspecting the O-ring seal and checking transmission fluid levels.

The old O-ring from the VSS should be removed and discarded.

The camshaft sensor and crankshaft sensor, depending on the engine type, should be checked for resistance and proper signal output.

The PCM uses the VSS input signal for several different engine, transmission, and radio control functions.

Disconnect the electrical connector and remove the sensor mounting bolt. Place a drain pan underneath the sensor before removing it.

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

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

The second speed sensor is located at the rear output shaft.

The VSS is triggered by a toothed rotor on the transmission output shaft.

The Vehicle Speed Sensor (VSS) is a permanent magnet generator mounted on the transmission.

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

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