Component Testing

Multifunction Intake Air Sensor

1. Vehicle OFF, disconnect the harness connector at the B75C Multifunction Intake Air sensor.
2. Test the IAT Sensor 2 by varying the sensor temperature while monitoring the air temperature with a thermometer. Compare the readings with the scan tool IAT Sensor 2 parameter. The values should be within 5%.
   • If not within the specified range 

     Replace the B75C Multifunction Intake Air Sensor.

   • Go to next step: If within the specified range 
3. All OK.

Testing with EL-38522-A

NOTE:

In-correct diagnosis will result if Circuit/System Testing is not completed before performing the following test.

1. Perform the following test using a EL-38522-A  Variable Signal Generator or equivalent, if available.
2. Ignition Off, connect the leads of the EL-38522-A  Variable Signal Generator as follows:
   1. Red lead to the signal circuit terminal 1 at the harness connector
   2. Black leads to ground
   3. Battery voltage supply lead to B+
3. Set the EL-38522-A  Variable Signal Generator to the following specifications.
   • Signal switch to 5 V
   • Duty Cycle switch to 50 % (Normal)
   • Frequency switch to 250 Hz
4. Ignition On, verify the scan tool IAT Sensor 2 parameters listed below are within the ranges listed below:
   • IAT Sensor 2 is between 248 - 252 Hz
   NOTE:

   Changing the frequency should cause a warmer or colder IAT 2 temperature.

   • IAT Sensor 2 is between 70 - 76°C (160 - 166°F)
   NOTE:

   Increasing or decreasing the duty cycle should have an inverse affect on humidity.

   • Intake Air Humidity Sensor is between 48 - 52%
   • If a parameter is not within the specified range 

     Replace the K20 Engine Control Module.

   • Go to next step: If all the parameters are within the specified range 
5. All OK.