CARTRIDGE AS-VALVE 1528332 - Caterpillar

Illustration 1 g03374038
Schematic for thedemand fan solenoidThis diagnostic code is associated with the cooling fan bypass solenoid which is also referred to as the "demand fan solenoid". The FMI 3 means that the ECM has detected an above normal voltage in the solenoid circuit.Conditions that could cause this diagnostic code to be activated are:
The energize circuit of the solenoid is shorted to another voltage source.
The ECM has failed. The failure of the ECM is unlikely.Note: Before performing this procedure, inspect the harness connectors that are involved in the circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, secure, and in good condition. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure. Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear these diagnostic codes when the original diagnostic code has been corrected. Note: The resistance of the solenoid coil should be 7.3 ohms at 20 °C (68.0 °F).Test Step 1. CHECK THE ENERGIZE CIRCUIT OF THE SOLENOID FOR A SHORT
Disconnect the negative battery cable and turn the key start switch to the OFF position.
Disconnect the machine harness connector from the solenoid. Disconnect the machine harness connectors J1 from the ECM.
At the machine harness ECM connectors, measure the resistance from contact J1-62 (wire H746-YL) to all of the other contacts that are used in the J1 connectors for the ECM.Expected Result:Each resistance measurement is greater than 5000 ohms. Results:
YES - Each resistance measurement is greater than 5000 ohms. The resistance measurement does not indicate a short in the machine harness. Proceed to Test Step 2.
NO - Each resistance measurement is not greater than 5000 ohms. There is a short in the machine harness. Repair: The short is between wire H746-YL and the circuit that has a low resistance measurement.For information on testing for short circuits and finding short circuits, refer to Testing and Adjusting, "Wiring Harness (Short Circuit) - Test". Repair the machine harness or replace machine harness.STOPTest Step 2. CHECK THE OPERATION OF THE ECMThe key start switch remains in the OFF position. The machine harness connectors for the solenoid and the ECM remain disconnected.
At the machine harness connector J1 for the ECM, use a 151-6320 Removal Tool to remove the solenoid energize wire H746-YL and socket at contact J1-62 from the harness connector.
Reconnect the machine harness J1 and J2 connectors to the ECM.
Reconnect the negative battery cable and Turn the key start switch to the ON position.
Observe the status of the active 1076-3 diagnostic code.Expected Result:The 1076-3 diagnostic code is no longer active. Instead a 1076-5 diagnostic code is now active.Results:
YES - The 1076-3 diagnostic code is no longer active. Instead a 1076-5 diagnostic code has been activated after the solenoid energize circuit was disconnected. The ECM has responded correctly to the open circuit condition in the solenoid circuit.
Reinstall the disconnected solenoid