Rick's Free Auto Repair Advice

OBDII sensors

OBDII sensors

The computer uses data from these OBDII sensors

Intake air temperature (IAT) sensor

IAT, intake air temperature sensor, engine coolant temperature sensor, MAP, MAF

Typical intake air temperature sensor (IAT)

to help calculate air/fuel mixtures. The IAT is usually located in the air duct from the air filter box to the throttle body. Or, it can be located after the throttle body somewhere in the upper plenum of the intake manifold.

In use, the computer looks at data from the engine coolant temperature (ECT) so it knows if the engine is cold, then it looks at the IAT to see the temp of the outside air. Finally, it looks at either the manifold

mass airflow, MAF, MAP, IAT, ECT

Typical mass airflow sensor (MAF)

absolute pressure (MAP) or the mass airflow

ECT, engine coolant temperature sensor, IAT, MAF, MAP

Typical engine coolant temperature sensor (ECT)

manifold absolute pressure, MAP, MAF, IAT, ECT

Typical manifold absolute pressure (MAP) sensor

(MAF) to determine the density of the air. Once it knows all those variables, it can determine a starting air/fuel mixture.

 

© 2012 Rick Muscoplat

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Posted on by Rick Muscoplat



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