John Deere 4490: Intake Air Humidity Fault

The system has detected an issue related to the intake air humidity. This may affect engine performance or emissions control. The fault is associated with the intake air humidity sensor or its circuit.

1. 1

   Intake air humidity sensor

2. 2

   Wiring to the intake air humidity sensor

3. 3

   Connections to the intake air humidity sensor

1. 1

   Inspect

   Inspect the intake air humidity sensor for physical damage or contamination.

2. 2

   Check

   Check the wiring and connections to the intake air humidity sensor for looseness, corrosion, or damage.

3. 3

   Test

   Test the intake air humidity sensor for proper operation using the manufacturer's recommended procedure.