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| Illustration 1 | g06016284 |
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Simplified Schematic for CID 1674 (Solenoid Return #1) | |
This diagnostic code is associated with the "Solenoid Return #1" circuit. FMI 04 indicates that the Brake ECM has determined that the voltage in the return circuit for the Automatic Retarder Control (ARC) solenoid is below normal.
For more information on the ARC solenoids, refer to Systems Operation, "Electrical Output Components" in this manual.
Conditions that could cause this diagnostic code to be activated are listed below:
- The return circuit for one or both solenoids are shorted to a ground source.
- The ECM has failed. ECM failure 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.
Test Step 1. CHECK THE "SOLENOID 1 RETURN" CIRCUIT FOR A SHORT TO GROUND
- Turn the key start switch and the disconnect switch to the OFF position.
- Disconnect all the solenoids shown in the schematic above.
- Disconnect the J1 and J2 harness connectors from the Brake ECM.
- At the machine harness connectors for the ECM, measure the resistance from the "Solenoid Return #1" contact J1-54 (wire J815-BK(Black)) and the frame ground location. Measure the resistance from the contact J1-54 (wire J815-BK(Black)) and all other J1 and J2 contacts that are used in the Brake ECM.
Expected Result:
Each resistance measurement is greater than 50 ohms.
Results:
- OK - Each resistance measurement is greater than 50 ohms. The measurement is not indicating that the "solenoid 1 return" circuit is shorted to a ground source. Proceed to Test Step 2.
- NOT OK - One or more of the resistance measurements are less than 50 ohms. There is a short in the machine harness. The short is between wire J815-BK(Black)and the circuit with the low-resistance measurement or frame ground.
Repair: For information on testing for short circuits and finding short circuits, refer to Testing and Adjusting, "Wiring Harness (Short Circuit) - Test" in this manual.
Repair or replace the machine harness.STOP
Test Step 2. CHECK THE STATUS OF THE DIAGNOSTIC CODE
Reference:
Testing and Adjusting, "Electrical Connector - Inspect"
- Inspect the harness connectors. Clean the contacts of the harness connectors. Check the wires for damage to the insulation that is caused by excessive heat, battery acid, or chafing.
- Perform a
45 N (10 lb) pull test on each of the wires that are associated with the sensor circuit. - Reconnect all harness connectors. Make sure that the connectors are fully seated. Observe that the clips for each connector are fastened securely.
- Turn the disconnect switch and the key start switch to the ON position.
- Operate the machine.
- Check the status of the CID 1674 FMI 04 diagnostic code.
Expected Result:
The CID 1674 FMI 04 diagnostic code is not active.
Results:
- OK - The CID 1674 FMI 04 is not active. The diagnostic code does not currently exist.
Repair: The initial diagnostic code was probably caused by a poor electrical connection or a short at one of the harness connectors. Resume normal machine operation.
STOP
- NOT OK - The CID 1674 FMI 04 diagnostic code is still active. The diagnostic code has not been corrected.
Repair: Check the circuit again. If available, use Caterpillar Electronic Technician (Cat® ET) to perform a wiggle test on the machine wiring harness. The wiggle test can detect momentary or intermittent shorts or opens in the machine wiring harness.
If the cause of the problem is not found, the ECM may have failed.A failure of the Brake ECM is unlikely. Verify that all possible causes of the diagnostic code have been investigated.
Prior to replacing an ECM, contact your dealer Technical Communicator (TC) for possible consultation with Caterpillar. This consultation may greatly reduce repair time.
If the ECM must be replaced, refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace" in this manual.STOP