MAT Sensor

[paulbenning]

Dose anybody know if a VN s2 has a MAT sensor ? where is it and what will the car do if faulty

[Darcon666]

I could be wrong, so please correct me anyone... I think the MAT sensor on the V6 is at the back of the manifold under the elbow for the TB.

As for what it does...."If the intake air temperature sensor is not reading accurately, the PCM may think the air is warmer or colder than it actually is, causing it to miscalculate the air/fuel mixture. The result may be a lean or rich fuel mixture that causes driveability symptoms such as poor idle quality when cold, stumble on cold acceleration, and surging when the engine is warm."

[Morton]

They're not dear, for less than $40 they're well worth replacing

[VNVacationer]

The MAT Sensor is one of the inputs used by the ECM to control the fuel injector pulse width. The ECM supplies a voltage and then monitors this voltage to the sensor which changes resistance depending on the air temperature being fed to the engine.

If you get a MAT sensor circuit fault the ECM will substitute a default temperature value of 55 degrees Celcius.

If you have a decent multimeter you can check its operation by the voltage at the ECM or the MAT sensor actual resistance.

Not sure if the test points are the same but on the series 1 the voltages are checked across C12 and A11 of the ECM. 4 to 5 volts when starting a cold engine on a cold day and 1 to 2 volts when the engines up to temperature.

Again for a series 1 but can't see the series 2 being much different the resistance across a disconnected MAT sensor should be aproximately 1800 ohms at 38 degress C, 3400 ohms at 20 degrees and 7500 at 4 degrees.

If anyone knows if the series 1 and 2 are the same maybe they can say or correct me.