HOUSING 4N0943 - Caterpillar

Illustration 1 g02153156
Schematic of the Flow Limit Pressure solenoid
This diagnostic code is associated with the Flow Limit Pressure solenoid. An FMI 06 diagnostic code means the ECM has determined the current of the solenoid circuit is above normal. Possible causes for this diagnostic code are listed below:
The Flow Limit Pressure solenoid has failed
The Flow Limit Pressure solenoid energize circuit is shorted to ground.
The Machine ECM may have failed (unlikely).Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes now, but clear those codes after the original diagnostic code has been corrected. Note: Poor connections are often the cause of a problem in electrical circuits. Before performing this procedure, inspect all of the harness connectors involved in the circuit. Verify that all of the connections in the circuit are clean, secure, and in good condition. If a problem is found with any of the connections: correct the problem and verify that diagnostic code CID 1590 FMI 03 is still active, before performing the following procedures. System Response:When this diagnostic code is active, the ECM will turn off the current to the failed solenoid.Test Step 1. CHECK THE SOLENOID, THE ECM, AND THE CIRCUIT CONNECTIONS IN THE MACHINE HARNESS.
Turn the disconnect switch and the key start switch to the OFF position.
Disconnect the machine harness connector from the Flow Limit Pressure solenoid.
Turn the disconnect switch and the key start switch to the ON position. Do not start the engine.
Observe the status of the CID 1590 FMI 06 diagnostic code. Expected Result:The CID 1590 FMI 06 diagnostic code remains active. Results:
YES - The CID 1590 FMI 06 code remains active. Disconnecting the solenoid did not change the code. The solenoid is NOT the cause of the problem.Repair: The machine harness has failed, or the ECM may have failed. Go to Test Step 2.
NO - The CID 1590 FMI 06 diagnostic code is no longer active, and has been replaced by an active CID 1590 FMI 05 diagnostic code. The ECM has detected a valid diagnostic code. Repair: The ECM, and the harness connections, are correct. The solenoid has failed.Perform Test Step 1 again, to verify the solenoid failure. Replace the solenoid. Go to Test Step 3Test Step 2. CHECK THE ENERGIZE CIRCUIT OF THE SOLENOID FOR A SHORT TO GROUND.
Turn the key start switch and the disconnect switch to the OFF position.
The harness connector remains disconnected from the Flow Limit Pressure solenoid.
Disconnect the J1 and J2 machine harness connectors from the Machine ECM.
At the ECM J2 harness connector, measure the resistance from the signal contact J2-9 (wire M737-WH(White)) to all of the other contacts used in the machine harness connectors for the ECM. Expected Result:Each resistance is more than 5000 ohms.Results:
YES - Each resistance is more than 5000 ohms. The harness is correct. Go to Test Step 3.
NO - Each resistance is NOT more than 5000 ohms. There is a short in the harness. The short is between J2-9 (M737-WH(White)) and the circuit with the low resistance.Repair: Repair,