GM 25036751 Sensor, Intake Air Temperature

The Intake Manifold Temperature (IMT) sensor is a thermistor that measures the temperature of the air entering the engine. It has a high resistance at low temperatures and vice versa. The PCM supplies a 5-volt signal to the sensor and measures the voltage to calculate the incoming air temperature. The sensor signal is used to adjust spark timing based on air density.

While making checks, do so using a high-impedance, 10-megohm digital multimeter, to avoid destroying the PCM. On models featuring an anti theft audio system, turn off the anti theft system prior to disconnecting the battery or interrupting the battery supply to the stereo. In certain cases, after the Check Procedure, a trouble code is set, so, to erase all the codes in the PCM, remove the PCM-B fuse or disconnect the cable from the negative terminal on the battery for thirty seconds. In some instances, it might be relevant to employ pins or straightened paperclips to backprobe on the sensor electrical connector cables; always turning special attention not to short the probes. The A/C compressor clutch is managed by the PCM; the clutch will not engage until the engine idle speed is raised due to the load applied. Verify that your battery voltage at the a/c clutch with ign on, a/c on; if there is no battery voltage then check the fusable link and wires for damage. In the event you find that the fuse is all right, you should attempt to find voltage to the A/C compressor clutch relay. The camshaft position sensor under the distributor cap relays cylinder identification to the PCM and is not part of the ignition system. Check to see if the sensor is getting battery voltage at the harness connector if not check the fuses and if wires are the issue. The crankshaft position sensor uses the change in the magnetic field every time the reluctor ring passes, and sends pulses to the PCM to assist in ignition timing and the control of fuel injection. The ECT sensor which is also a thermistor changes its resistance to the flow of current with temperature and thus alters the voltage output which is fed to the PCM. Check whether the ECT is getting reference voltage and check the resistance of the ECT at cold as well as at normal operating condition. The IAC valve regulates the low speeds of the engine to control the driving of automobile whereas the IAT is a sensor whose function is to measure the temperature of intake air which it alters the voltage signal to the PCM. Knock sensor rules an engine knock, as the PCM states that the ignition timing be changed. The MAP sensor monitors the change in pressure inside the intake manifold and translates the same into voltage for the purpose of fuelling and controlling ignition timing. The MAF sensor relates to the airflow quantity entering the engine and the oxygen sensor measures the exhaust gas oxygen content. The Park/Neutral switch does not allow the engine to start unless the gear is in Park or Neutral and the power steering pressure switch raises idle rate under load. The TPS is installed on the throttle body and is responsible for monitoring the position of throttle valve in order to supply fuel and the VSS provides pulsing voltage signal to the PCM to be converted to mph.

If a coolant temperature sensor wire circuit provides a flawed reading it may signal Code 14 or Code 15 to need wiring repair or sensor to be changed. To remove the sensor, the locking tab on the connector should be released and the connector disconnected from the sensor, the screw of the sensor should be unscrewed very slowly. Lay hands on the coolant sensor delicately since normal impacts can interfere with the operation of the fuel injection system. To improve its anti leakage and anti corrosion capability, wind round some Teflon sealing tape around the threads of the new sensor before installing and finally tightening it. Cases where the Manifold Air Temperature (MAT) sensor fixed at the air cleaner housing will cause Code 23 or Code 25. To remove it, disconnect the wire harness and unscrew the sensor; to install it follow the inverse procedure. The Manifold Absolute Pressure (MAP) sensor monitors pressure fluctuations in the intake manifold due to load or speed of the engine; failure results to code 33 or code 34 and affects fuel supply and timing of the ignition. Exhaust oxygen sensor, installed in the exhaust manifold, controls oxygen content and assists ECM to modify the fuel mix. The presence of an open oxygen sensor triggers Code 13 while low and high voltage conditions trigger both Code 44 and Code 45, the symptoms of which can also be associated with fuel system problems. The Turbocharger Boost Control Solenoid is a solenoid located in the intercooler pipe and is controlled by the ECM with reference to boost pressure and engine speed; a faulty Turbocharger Boost Control Solenoid may cause Code 23 which can result in turbocharger lag and richness in fuel delivery. The Park/Neutral switch informs the ECM when the transaxle is in Park or Neutral, which affects Transaxle Converter Clutch and idle air control valve; if this switch is disconnected while driving, it will cause idle quality problems and false codes. The ECM is connected to the starter solenoid to monitor engine cranking while the A/C 'On' signal in turn helps the A/C selector switch position for change in idle speed. The vehicle speed sensor transmits a pulse voltage signal to the ECM and this is converted into miles per hour to control TCC system, the distributor incorporates signals to ECM concerning the rpm and crankshaft position of the engine.

To test the sensor, connect a digital ohmmeter and compare the resistance to the ambient air temperature. Heat the sensor slightly and observe the temperature and resistance. If the sensor does not meet specifications, it should be replaced.

The MAP sensor monitors intake manifold pressure changes and converts this information into a voltage output for the ECM to control fuel delivery and ignition timing.

Wrap the threads with Teflon sealing tape to prevent leakage and corrosion.

No, the sensor will need to be assembled once received

This sensor is a 3/"x18 NPTF