Pontiac 19178930 Sensor Asm,Heated Oxygen

The oxygen sensor is a device that produces a voltage when exposed to oxygen in the exhaust gases. It is in the exhaust system and can be heated internally for faster reaction. The sensor produces a voltage between zero and one volt, with a low voltage indicating a lean mixture and a high voltage indicating a rich mixture. The stoichiometric air to fuel ratio causes the voltage to fluctuate.

The oxygen sensor is mounted in the exhaust manifold and its function is to measure the oxygen content of the exhaust gas stream and to produce an output voltage in the range 0.1 volt to 0.9 volts where a low voltage corresponds to a high oxygen concentration, or rich mixture, to a low voltage corresponding to a low oxygen concentration, lean mixture. The ECM uses this variable voltage to adjust the particulars of the fuel-to-air mixture with an ideal balance of 14.7 air to 1 fuel in order to obtain the least exhaust emission and optimized catalytic converter functioning. The sensor does not generate voltage below the typical operating temperature of about 600-degrees F, so the ECM runs in open-loop during warm-up. If the engine stays normal temperature and the sensor provides a constant voltage of 0.35 to 0.55 volt, and the TPS shows it is not at idle a Code 13 is stored. A failure to operate for two minutes or more or low voltage or short circuit produces the Code 44, while a high voltage signal produces the Code 45. In these case the ECM drops out to a preset value to fuel delivery rather than using feedback from the sensor. For correct operation of the sensor, its electric contacts have to be clean and well-connected to enable electricity flow, there has to be a proper air circulation around the sensor so that the operating temperature is reached and the fuel used contains no lead. Several precautions should not be made during servicing among them being, do not remove the permanently attached pigtail and connector, do not allow contaminants to come near the electrical connector and the sensor end, do not clean with solvents, handle the sensor tenderly and ensure that the silicon boot is well placed. when replacing the sensor it may be tight if the engine is cold and can be eased if the engine is run for a bit. The procedure includes removing the battery, lifting the car, removing the electrical connector, capturing the position of the silicone boot, unscrewing the sensor loosely, applying some anti seize compound on the threads of the sensor, putting the new sensor and tightening it, connecting the electrical connector, grounding the car and reconnecting the battery.

Wrap the threads with Teflon sealing tape to prevent leakage and corrosion, with installation being the reverse of removal.

The engine coolant temperature (ECT) sensor is a thermistor that changes resistance with temperature. To check it, measure the resistance while cold and warm, and ensure the reference voltage from the PCM is around 5.0 volts.

You should be careful to avoid damaging or removing the pigtail or electrical connector, as this will render the sensor useless.

The knock sensors detect engine knock. To check them, you should check for reference voltage and resistance.

The knock sensors detect engine knock. To check them, you should check for reference voltage and resistance.

Hall effect sensors produce ON/OFF signals to the PCM and should show voltage readings when the engine is rotated.

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.

It measures the air entering the engine and may be absent in some engines, which instead have a MAP sensor.