FiatAgri 4: Unknown Issue / Model Dependent Fault

Fault code 4 is not a standardized code and its meaning depends entirely on the specific machine model and the electronic control module logging the fault. Depending on the system, it can indicate an open circuit in the fuel level sender, an autopilot A/D scan timeout, low hydraulic charge pressure, or engine-related faults such as a clogged EGR valve, faulty fuel shut-off solenoid, or air mass flow sensor issues. Accurate diagnosis requires identifying the specific controller displaying the code.

• 5640
• 6640
• 7740
• 7840
• 8240
• 8340
• S90
• S100
• Intellisteer™ equipped tractors
• TC33D
• T8000 Series
• TG Series
• LS180
• LS190

1. 1

   Identify the specific control module logging the fault (e.g., Instrument Cluster, Engine, Transmission, or Guidance) to determine which system is affected.

2. 2

   For Fuel Level Sender faults (EIC module): Inspect the wiring harness between the fuel level sender and the instrument cluster for visible damage, corrosion, or loose connections.

3. 3

   For Fuel Level Sender faults (EIC module): Check the fuel sender unit for internal failure.

4. 4

   For Engine faults (ECM module): Listen for an audible 'click' from the fuel shut-off solenoid when the key is turned, and check its wiring.

5. 5

   For Engine faults (ECM module): Inspect the EGR valve for blockages.

6. 6

   For Engine faults (ECM module): Check the Air Mass Flow sensor's electrical connector, wiring, and test its voltage output.

7. 7

   For Hydraulic faults (TCU/Hydraulic controller): Check hydraulic fluid levels and inspect for a plugged hydraulic charge filter.

8. 8

   For Hydraulic faults (TCU/Hydraulic controller): Verify hydraulic charge pressure is within manufacturer specifications.

1. 1

   Repair fuel sender wiring

   If diagnosing a fuel level sender open circuit, repair any damaged wiring or connectors between the sender and the Electronic Instrument Cluster (EIC).

2. 2

   Replace fuel level sender

   If the fuel level sender has an internal failure, replace the sender unit.

3. 3

   Service EGR valve

   If diagnosing an engine EGR fault, clean or replace the clogged EGR valve.

4. 4

   Replace fuel shut-off solenoid

   If the fuel shut-off solenoid is faulty or not clicking, replace the solenoid and repair its circuit as needed.

5. 5

   Repair or replace Air Mass Flow sensor

   If diagnosing an MAF fault, repair damaged wiring or replace the Air Mass Flow sensor.

6. 6

   Service hydraulic system

   If diagnosing a hydraulic charge pressure fault, top up hydraulic fluid, replace the hydraulic filter if clogged, and inspect for leaks. Further diagnosis of the hydraulic pump may be necessary if pressure issues persist.