Case IH 3005 (DTC 4B84) - ECU – Engine Control Unit (ECU A-095): Air filter clog or circuit failure

This fault code indicates that the control module has detected a restriction in the engine's air intake system (a clogged air filter) or there is an electrical circuit failure (open, short, or damaged wiring) related to the air filter clogging switch.

• MAXXUM T4E
• 240 Series (7240, 8240, 9240)
• 230 Series (7230, 8230, 9230)
• Magnum series (MX210, MX230, MX255, MX285)
• Puma series
• Farmall series

1. 1

   Use the Electronic Service Tool (EST) to check if the fault is currently active. If inactive, the issue may be intermittent.

2. 2

   Look for related fault code 3014 (DTC 4C84) ('Air filter clog or circuit failure present for a long time'). If active, diagnose it in tandem.

3. 3

   Inspect the engine air filter and the entire air intake system for heavy dirt accumulation, debris, or physical blockages.

4. 4

   Verify that the tractor/machine battery has not been connected to an external power supply. If an external power supply is connected, disconnect it and test the system for normal operation.

5. 5

   Visually inspect the wiring harness and connectors associated with the air filter clogging switch (S-022). Look for bent or dislocated pins, corroded terminals, or broken wires. Flex the harnesses while monitoring the EST to check for intermittent electrical drops.

1. 1

   Address Physical Clogs

   If the diagnostic inspection reveals a dirty or blocked air filter, remove and replace the primary (and secondary, if applicable) engine air filters. Clear any debris from the intake housing.

2. 2

   Test the Switch and Wiring

   If the filters are clean, test the S-022 Air Filter Clogging Switch and its circuit. The switch is typically a pressure contactor switch (e.g., 65 mBar) located on the air inlet pipe between the air filter and the turbocharger. Verify continuity between the switch connector and the ECU A-095.

3. 3

   Repair/Replace Components

   Repair any damaged wiring. If the wiring is intact but the switch fails continuity/pressure testing, replace the S-022 switch.

4. 4

   ECU Software Check

   If the physical filter, switch, and wiring all test perfectly but the fault remains active, Case IH manuals dictate checking the ECU A-095 for the appropriate software version. Re-flash the ECU software if necessary.

5. 5

   Clear and Verify

   Once repairs are made, use the EST to clear the fault codes and return the machine to service to verify normal operation.