John Deere 4490.12 – ECU: Intake Air Humidity Fault / The Intake Air Temperature Sensor/Pressure/Humidity Has A Fault.

The engine's intake air sensor (Tri-CAN sensor) has detected an internal error or a problem with measuring the intake air humidity.

• 5085E
• 5090E
• 5090EL
• 5100E
• 5085M
• 5100M
• 5100MH
• 5100ML
• 5115ML
• 5090M
• 5115M
• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 5M Series
• 6M Series
• 6R Series
• 8R/8RT Series
• 8245R
• 8400R
• 9RT Series
• 9470RT
• 9520RT
• 9570RT
• 7180
• 7280
• 7380
• 7480
• 7580
• 7780
• 7980
• 770G
• 450K
• 550K

1. 1

   Check for ECU software updates (e.g., software revision SW60672L) to prevent false setting of the code.

2. 2

   Inspect wiring and connections associated with the intake air humidity sensor circuit for damage, fraying, or looseness.

3. 3

   Check the sensor element and mounting location in the intake piping for excessive dust, oil, or moisture buildup.

4. 4

   Test the sensor circuit for continuity and correct voltage levels using a multimeter.

1. 1

   Power Down

   Turn off the engine, remove the key, and ensure the machine is properly secured.

2. 2

   Locate the Sensor

   Locate the Engine Air Intake Turbo Sensor (Tri-CAN sensor) on the engine's air intake/turbocharger piping.

3. 3

   Disconnect

   Carefully unplug the electrical wiring harness connector from the sensor.

4. 4

   Remove

   Unbolt or unthread the faulty sensor from the intake piping.

5. 5

   Install

   Install the new Tri-CAN sensor into the intake piping and secure it.

6. 6

   Reconnect

   Plug the electrical harness back into the new sensor, ensuring the connector clicks and locks into place.

7. 7

   Clear Codes

   Turn the key on and use a John Deere diagnostic tool (Service ADVISOR) to reset the ECU, clear the 004490.12 fault code, and monitor the live data to ensure accurate humidity measurement is restored.