DUCT-AIR 2858654 - Caterpillar

Illustration 1 g00951780
Schematic of the relays (auxiliary diverter valve)This diagnostic code is associated with the relays (auxiliary diverter valve). The FMI 06 means that the ECM has determined that the current of the relay is above normal. The possible causes of this diagnostic code are listed:
The energize circuit of the relay is shorted to ground.
The relay has failed.
The ECM has failed. This is unlikely. 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. Ensure that the diagnostic code of CID 1820 FMI 06 is active before performing this procedure.Note: Use the 146-4080 Digital Multimeter for the measurements in this procedure.System Response:The diagnostic code of CID 1820 FMI 06 will be logged in the internal memory of the Machine ECM.Test Step 1. CHECK THE RELAYS.
Turn the disconnect switch and the key start switch to the ON position. Do not start the engine.
Observe the status of the diagnostic code.
Disconnect the relays with the active diagnostic code from the machine harness. Expected Result:CID 1820 FMI 06 changes to CID 1820 FMI 05 when the relay is disconnected.Results:
YES - CID 1820 FMI 06 changes to CID 1820 FMI 05 when the relay is disconnected. The circuit is correct.Repair: The relay has failed. Repeat this test "CHECK THE RELAY" in order to verify the failure of the relay. Replace the relay. Stop.
NO - CID 1820 FMI 06 remains active. Proceed to Test Step 2.Test Step 2. CHECK THE ENERGIZE CIRCUIT OF THE RELAY FOR A SHORT TO GROUND.
Turn the key start switch and the disconnect switch to the OFF position.
The relays remain disconnected from the machine harness.
Disconnect the machine harness connector(s) from the ECM.
At the machine harness connector, measure the resistance from the signal contact J1-66 (wire 794-YL) to all contacts that are used in the machine harness connectors for the ECM. Expected Result:Each resistance measurement is greater than 5000 ohms.Results:
OK - Each resistance measurement is greater than 5000 ohms. The machine harness is correct. Proceed to Test Step 3.
NOT OK - Each resistance measurement is not greater than 5000 ohms. There is a short in the machine harness. The short is between J1-66 (wire 794-YL) and the circuit with the low resistance measurement.Repair: Repair the machine harness or replace the machine harness. Stop.Test Step 3. CHECK IF THE DIAGNOSTIC CODE REMAINS.
Inspect the harness connectors and clean the contacts of the harness connectors.
Reconnect all harness connectors.
Turn the disconnect switch and the key start switch to the ON position.
Operate the machine.
Check the status of the CID 1820 FMI 06. Expected Result:The CID 1820 FMI 06 is active. Results:
YES - The CID 1820 FMI 06 is active. 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. If the cause of the diagnostic code is not found, replace the ECM. See Testing and Adjusting, "Electronic Control Module (ECM) -