The Engine Coolant Temperature (ECT) sensor is normally located near the thermostat or at any rate, wherever the thermostat is mounted; for the Luxgen 3.4L, the sensor is sited towards the rear of the right cylinder head on the lower intake manifold . It also works as a thermistor, that is, its resistance decreases or increases depending on the temperature. When you plan to install a new sensor, it is better to thread the wires with Teflon sealing tapes to avoid leakage and corrosion. In order to uninstall the sensor, one has to unlock the locking tab, disconnect the electrical connector and, carefully, unscrew the sensor as its damage might provoke a failure in the fuel injection system. Installation is done in the reverse sequence as well, and levels of coolant have to be checked afterward. MAF is an intake air sensor mounted in the air intake tube between throttle body and air cleaner housing or on the throttle body on 1995 and later 3800 models. It measures the air, getting into the engine and, in some engines, it could be supplemented by the MAP sensor. To remove the MAF sensor, one has to unplug the electrical connector, unscrew the clamps and then remove it. For the 1995 and later 3800 engines to remove the sensor one has to take out screws thus to interpolate it one has to reverse the procedure of removal. The Manifold Absolute Pressure (MAP) sensor is located at the front of the engine on 1995 and later 3800 engines, this is on the upper intake manifold or firewall. It also checks on changes in the intake manifold pressure occasioned by changes in the engine load and speed. To dismantle it, first, disconnect the vacuum hose, pull the electrical connector and then unbolt the mounting screws. On 3.4L models, the retaining bracket and bolt must be removed, then pull it straight up; On 1995 and later models, the retaining clips must be disengaged. The Intake Air Temperature or (IAT) sensor is located downstream of the air filter, or in the housing of the air cleaner and performs the thermistor role. To remove it, disconnect the electrical connect or unscrew or twist it from its place and for installation twisting or screwing the electrical connector in place is done. Instruments called oxygen sensors, fitted in the exhaust manifold or pipe, measure the oxygen in the exhaust emissions and supply a voltage signal to the PCM to regulate the mixture. These are the following special precautions for the pigtail and the electrical connector; no contact with contaminants, and must have ample airflow to the IP67 rating standard. To remove an oxygen sensor, you have to remove the battery, lift the car, remove any heat shields around the sensor, remove an electrical connector and then unscrew the sensor; before tightening the new sensor, apply anti seize to the threads. Tps is an electro-mechanical device positioned on the throttle shaft of the throttle body whereby its main function is to detect the position of the throttle valve. Crankshaft position sensors depends with the kind of engine as some may have a single sensor and others a dual sensor which are all used to monitor crankshaft position and speed for ignition control. Replacement entails removal of the battery, the electrical connector as well as the sensor, while installment is the process of the vice versa. This is typically found at the front of the engine block or may be mounted on the left cylinder head and generates a signal for the PCM for the intake stroke of number one piston. The Vehicle Speed Sensor (VSS) is installed at the rear of the transaxle housing which employs an electrical pulse and voltage signal to the PCM for the measurement of speed. In its stead, pull the retaining bolt and disconnect the sensor. Controls the park/neutral function when the automatic transaxle is engaged and controls various systems based on whether the transaxle is in 'Park' or 'Neutral'; should not be disconnected during driving. Part of the steering gear, the Power Steering Pressure Switch conveys information to the PCM about high hydraulic pressure and influences engine idle and air conditioning; to remove it, one has to detach the electrical connector and unscrew the sensor.
Posted by GMPartsGiant Specialist 
