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| Illustration 1 | g01302684 |
Connections for the Real Time Clock circuit of the IQAN-MDM | |
This diagnostic code is associated with the power signal that is supplied to the IQAN-MDM module at pin 3 and pin 5 of the IQAN-MDM module. The "RTC+ NOT CONNECTED" code means that the voltage supply to the module is not the nominal voltage of 24 VDC.
The possible causes of this diagnostic code are listed below:
- The power supply is unable to deliver the nominal system voltage.
- The energize circuit of the module is open in the harness.
- The 10 amp MDM Memory fuse is blown.
- The module has failed. This is unlikely.
Test Step 1. CHECK THE POWER SUPPLY FOR THE MODULE
- Turn the disconnect switch and the key start switch to the ON position.
- Check the voltage at the mating connector pins on the IQAN-MDM module from contact 3 (wire 200-BK) to contact 5 (wire 163-RD).
Expected Result:
The voltage measurement is approximately 24 VDC.
Results:
- YES - The voltage measurement is approximately 24 VDC. The module power supply is correct. Proceed to Test Step 2.
- NO - The voltage measurement is not approximately 24 VDC. There is a problem with the voltage supply for the module.
Repair: The voltage supply circuit (wire 163-RD) for the module is open in the machine harness. Ensure that the MDM Memory fuse is not open. Refer to the complete machine Electrical System Schematic. Examine all of the connections that are in the supply circuit between the fuse and the module. Ensure that the connections are clean, secure and in good condition. Repair the machine harness or replace the machine harness.
STOP
Test Step 2. CHECK THE STATUS OF THE DIAGNOSTIC CODE
- Inspect the harness connectors and clean the contacts of the harness connectors and 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 circuit.
- Reconnect all harness connectors making sure that the connectors are fully seated and the clips for each connector are completely fastened.
- Turn the disconnect switch and the key start switch to the ON position.
- Operate the machine.
- Check the status of the "RTC+ NOT CONNECTED" code.
Expected Result:
The "RTC+ NOT CONNECTED" code is active.
Results:
- YES - The "RTC+ NOT CONNECTED" code is active. The diagnostic code has not been corrected.
Repair: If the diagnostic code is still active, the module may be faulty.Prior to replacing a module, always contact your dealership's Technical Communicator for possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the cause of the diagnostic code is not found, replace the module.
STOP
- NO - The "RTC+ NOT CONNECTED" code is not active. The diagnostic code does not exist at this time.
Repair: The initial diagnostic code was probably caused by a poor electrical connection at one of the harness connectors that was disconnected and reconnected. Resume normal machine operation.
STOP