320E and 323E Excavators Machine Electronic Control System MID 299, 5322-4 Caterpillar

Conditions Which Generate This Code:

Illustration 1	g06010793
Schematic of the "Solenoid Return 6" circuit associated with the "Stick Cylinder Extend" solenoid.

The "Solenoid Return 6" diagnostic code is associated with the "Stick Cylinder Extend" solenoid. The FMI 04 diagnostic code means that the ECM has determined that the circuit voltage is below normal.

The possible causes are listed below:

• There is an open in the circuit.

• The harness is shorted to ground.

• The solenoid has failed.

• The Machine ECM has failed. A failure of the ECM is unlikely.

Note: The following procedure can create numerous related diagnostic codes. When all harnesses are reconnected, the related diagnostic codes will be shown as being not active. Clear all related diagnostic codes after this procedure is completed.

Note: Ensure that the diagnostic code for the return is active.

Test Step 1. CHECK THE Machine harness FOR AN OPEN.

1. Turn the key start switch and the disconnect switch to the OFF position.

2. Disconnect the machine harness connector 3 from the Cat Grade Control ECM.

3. Connect a jumper wire between the signal contact and the return contact at the solenoid harness connector.

4. At the ECM side of the machine harness, measure the resistance between the signal and return contact.

Expected Result:

The resistance should be less than 5 ohms.

Results:

• YES - The resistance is less than 5 ohms. The machine harness is correct. Proceed to test step 3.

• NO - The resistance measurement is NOT correct. There is an open circuit in the machine harness.

  Repair: The open is in the wire for the solenoid signal or the return wire of the machine harness. Repair the machine harness or replace the machine harness.

  Proceed to test step 3.

Test Step 2. check the harness for a short to ground.

1. The key start switch and disconnect switch remain in the OFF position.

2. The Cat Grade Control ECM and solenoid remain disconnected from the machine harness.

3. Removed the jumper wire installed during the previous test step.

4. Measure the resistance between the signal contact and frame ground. Record the measurement.

5. Measure the resistance between the return contact and frame ground. Record the measurement.

Expected Result:

Each reading is greater than 5K ohms.

Results:

• OK - - The reading is greater than 5K ohms, the harness is correct. Proceed to test step 3.

• NOT OK - - One or both of the readings are less than 5 ohms.

  Repair: A short exists in the circuit where the low resistance was observed. Repair or replace the machine harness.NOTE: A resistance greater than 5 ohms but less than 5K ohms indicates a loose or corroded connection in the circuit. A resistance greater than 5K ohms indicates an open in the circuit.

  Proceed to test step 3.

Test Step 3. CHECK IF THE DIAGNOSTIC CODE REMAINS.

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

2. Reconnect all harness connectors.

3. Turn the disconnect switch and the key start switch to the ON position.

4. Clear all inactive diagnostic codes.

5. Operate the machine.

6. Stop the machine and place the parking brake switch in the ON position.

7. Check if the diagnostic code for the solenoid is active.

Expected Result:

The diagnostic code is NO longer active.

Results:

• YES - The diagnostic code is NO longer active. The diagnostic code does not exist currently. The initial diagnostic code was probably caused by a poor electrical connection or a short at one of the harness connectors.

  STOP

• NO - The diagnostic code has not been corrected.

  Repair: A failure of the Machine ECM is unlikely. Exit this procedure and perform this procedure again. If the cause of the diagnostic code is not found, replace the Machine ECM. Prior to replacing an ECM, always contact your dealership for possible consultation with AVSpare. This consultation may greatly reduce repair time. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace".

  STOP