IDLER GP-FRONT 2249980 - Caterpillar

Illustration 1 g03425561
Schematic of the Hydraulic Lock solenoid circuit for the 312D2, 313D2, and 318D2 series machines.This diagnostic code is associated with the "Hydraulic Lock" solenoid. The FMI 03 diagnostic code means that the Machine ECM has determined that the voltage of the solenoid circuit is above normal.
Possible Causes for an FMI 3 diagnostic code are:
The power circuit of the switch is shorted to a higher voltage source.
The switch has failed
The Machine ECM has failed. This situation is unlikely.Test Step 1. CHECK THE MACHINE HARNESS FOR A SHORT.
Turn key start switch and disconnect switch OFF.
Disconnect the harness connection at the relay.
Disconnect J1 and J2 connectors from the Machine ECM.
Measure resistance of the relay signal contact to all J1 and J2 connectors.Expected Result:Each reading is greater than 5K Ω.Results:
OK - All resistance measurements are greater than 5K ohms. Proceed to Test Step 2.
NOT OK - One or more readings are less than 5 ohms.Repair: A short exists between the signal contact and the circuit with the low resistance. Repair or replace the machine harness.Note: A resistance that is greater than 5 ohms but less than 5K ohms would indicate a loose or corroded connection in the circuit. A resistance measurement greater than 5K ohms indicates an open in the circuit. STOPTest Step 2. CHECK THE SOLENOID.
Reconnect all harness connections.
Turn key start switch and disconnect switch ON.
Disconnect the "Hydraulic Lock " solenoid from the machine harness.
Observe the status of the active CID 1160 FMI 03 diagnostic code. Expected Result:When the relay is disconnected, the status of the active CID 1160 FMI 03 diagnostic code changes to a CID 1160 FMI 05 code.Results:
OK - All of the checks for the relay are correct. The relay is not the cause of the problem. The CID 1160 FMI 03 diagnostic code is still active. Proceed to Test Step 3.
NOT OK - The CID 1160 FMI 05 diagnostic code became active when the relay was disconnected. Repair: Verify that the relay has failed by substituting a known good relay that is the same part number for the suspect relay. Replace the faulty relay.STOPTest Step 3. CHECK THE ENERGIZE CIRCUIT OF THE SOLENOID FOR A SHORT TO THE +BATTERY CIRCUIT.
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the wires from the back of the connector at the ECM.
Turn the key start switch and the disconnect switch to the ON position. Do not start the engine.
At the machine harness connector for the solenoid, measure the voltage from contact 1 (wire A588-GN) to frame ground. Expected Result:The voltage is 0 VDC.Results:
OK - There are no shorts in the wire. Proceed to Test Step 4.
NOT OK - A voltage is present in the wires. There is a short in the machine harness or in the wire. The short is to a separate voltage source.Repair: Repair the machine harness or replace the machine harness. Ensure that the fix has corrected the problem.STOPTest Step 4. CHECK IF THE DIAGNOSTIC CODE IS STILL ACTIVE.
Inspect the harness connectors.