259D Skid Steer Loaders Machine Systems – MID 039 – CID 1936 – FMI 03

Conditions Which Generate This Code:

Illustration 1g03371909

Schematic of the High Flow Relay

This diagnostic code is associated with the Hydraulic System High Pressure Solenoid. This diagnostic code is recorded when the ECM detects a short to the +battery in the electrical path. The electrical path goes from the ECM to the solenoid and back to the ECM. The return circuit is connected for all solenoids. The return circuit connects to contact J2-4 (wire H807-YL) of the Machine ECM.

The possible causes of this diagnostic code are listed:

  • The signal circuit from the ECM to the solenoid valve is shorted to the +battery.

  • The return circuit from the solenoid valve is shorted to the +battery.

System Response:

The machine response is listed:

  • All electrohydraulic valves are turned off.

  • The pilot on/off solenoid valve is turned off.

  • Implement functions are disabled until the fault is corrected and the levers are centered.

Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when the original diagnostic code is corrected.

Note: Ensure that the diagnostic code is active and that the diagnostic code indicator is active.


  1. Disconnect the negative battery cable and turn the key start switch to the OFF position.

  1. Disconnect the machine harness from the solenoid.

  1. Disconnect J1 and J2 machine harness connectors from the ECM.

  1. At the machine harness connector, measure the resistance from signal contact J2-5 (wire G970-BU) to all contacts that are used in the machine harness connectors for the ECM.

Expected Result:

Each resistance measurement should be greater than 5000 ohms.


  • OK - Each resistance measurement is greater than 5000 ohms. The machine harness is correct. Proceed to test step 2.

  • NOT OK - One or more resistance measurements is not correct. There is a short in the machine harness. The short is between signal contact J2-5 (wire G970-BU) and the circuit with the low resistance measurement. Repair the machine harness or replace the machine harness.STOP


  1. Inspect the contacts of the harness connectors and clean the contacts.

  1. Reconnect all harness connectors.

  1. Reconnect the negative battery cable and turn the key start switch to the ON position.

  1. Clear all of the logged diagnostic codes.

  1. Operate the machine.

  1. Check if the CID 1936 FMI 03 is present.

Expected Result:

The diagnostic code for the solenoid is NOT present.


  • YES - The diagnostic code is NOT present. The diagnostic code does not exist at this time.

    Repair: The initial diagnostic code was probably caused by a poor electrical connection or a short at one of the harness connectors that was disconnected and reconnected. Resume normal machine operation.


  • NO - The diagnostic code has not been corrected. The ECM may have failed.

    Repair: It is unlikely that the ECM has failed. Exit this procedure and perform this procedure again. Exit this procedure and perform this procedure again. If the cause of the diagnostic code is not found, contact your dealership's Technical Communicator for possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the ECM requires replacement, refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace"


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