Where Is the Mass Air Flow in a 2001 Toyota Corolla?

The mass airflow sensor also called an airflow meter on a 2001 Corolla performs two functions, as it also contains an intake air temperature sensor. The MAF sensor side measures the density of the air entering the intake via a hot wire. The MAF sensor then relays this signal to the engine control module, which in turn adjusts ignition timing, fuel injection and oxygen sensor heater, as needed. Before installing a new MAF sensor on a 2001 Corolla, you must find and test it to make certain the part needs to be replaced.

Instructions

Locating the Mass Airflow Sensor

1

Open the Corollas hood.

2

Find the air filter box on the drivers side of the engine compartment.

3

Trace the air filter box toward the passenger side of the Corolla until you find the electrical component bolted to the top of the air filter box, just before the plastic air filter box outlet tube. The component is the mass airflow sensor.

Testing the Mass Airflow Sensor

4

Press and hold the unlocking button on the MAF sensors wiring harness and pull the harness from the sensor.

5

Remove the two bolts securing the MAF sensor in the air filter box by using a ratchet and socket. Pull upward on the MAF sensor with a slight twisting motion to remove it.

6

Examine the sensor with the probe of the MAF sensor -- the part that inserts into the air filter box -- facing down and the receptacle facing you. The pin on the far left of the receptacle is the E2 pin and the one to the right of the E2 is labeled as the "THA" pin.

7

Set a multimeter to measure ohms and touch one of the multimeters probes on the E2 pin and the other on the "THA" pin. The resistance between these two pins depends on the air temperature. If the outside temperature is between the temperatures listed, the ohms should measure between the two ranges. At -4 degrees Fahrenheit, the resistance should be 13,600 to 18,400 ohms. At 68 degrees F, the resistance should be 2,200 to 2,700 ohms and at 140 degrees F, the resistance should be 500 to 700 ohms.

8

Proceed to the section Installing the Mass Airflow Sensor to install a new MAF sensor if the MAF sensor does not meet the specifications in step 4. If the sensor does meet specifications, proceed to the section Installing the Mass Airflow Sensor and use that process to install the original MAF sensor.

Installing the Mass Airflow Sensor

9

Align the MAF sensor with its hole in the top of the air filter box. Press the MAF sensor into the air filter box until its inserted fully.

10

Thread the MAF sensor bolts, then snug them with a ratchet and socket. Toyota does not provide a torque specification for the MAF sensor bolts.

11

Plug the wiring harness into the receptacle on the new MAF sensor.