This code occurs when:
This code occurs when:
The PL522 or 523 module tracks machine operating hours for reporting to the office. The alternator R-terminal signal is used to
detect when the machine is operating.
If the input continuously receives voltage signals above the normal range, machine operation cannot be detected. Simultaneously, the reported timekeeping unit (SMU) will be inaccurate.
Step 1. Check if the R-terminal cable is short-circuited to the battery. A. Disconnect the PL522 or 523 cable (P1>) from the PL522 or 523 module.
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B. Measure the resistance from the alternator R-terminal input J1-4 (403MC9-GN-18) to the battery (J1-1).
Expected Result: The resistance should be greater than 5000 ohms.
Result: • Normal - The PL522 or 523 harness appears normal. Proceed to Test Step 2.
• Abnormal - The PL522 or 523 cable may be short-circuited to the battery. Repair: Repair the cable and confirm the fault has been eliminated.
Stop Test Step 2. Check if the PL522 and 523 harnesses are short-circuited to the voltage source. A. A. Disconnect the PL522 or 523 cable (P1) from the PL522 or 523 module.
B. Start the engine.
C. Measure the alternator R-terminal input (J1-4) to confirm a square wave of 11VDC to 32VDC. The measurement result should be in the range of 5Hz to 2kHz, or a stable DC voltage equivalent to the battery voltage should be present.
Expected result: No stable DC voltage equivalent to the battery voltage was measured when measuring the alternator R-terminal input.
Result: • Normal – The signal is a square wave of 11VDC to 32VDC. The measurement result should be in the range of 0Hz to 2kHz. Within the kHz range,
or there exists a stable DC voltage equivalent to the battery voltage. The PL522 or 523 harness may not be faulty. Proceed to Test Step 3.
·Abnormal - The PL522 or 523 cable may be short-circuited to the DC power supply, not the battery power supply.
Repair: Repair the cable and confirm the fault has been eliminated.
Stop Test Step 3. Check the machine alternator.
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A. Disconnect the PL522 or 523 machine cable from the alternator.
B. Start the engine.
C. Use a multimeter to measure the alternator R-terminal to confirm a square wave of 11VDC to 32VDC. Measurement
Expected Result: 3. Five. There should be a 0kHz to 2kHz square wave on the alternator R-terminal. A 11VDC to 32VDC square wave is detected.
Results: • Normal - A 0kHz to 2kHz 11VDC to 32VDC square wave is detected at the alternator R- terminal. Proceed to Test Step 4.
• Abnormal - No 0kHz to 2kHz 11VDC to 32VDC square wave is detected at the alternator R- terminal.
Repair: Repair or replace the alternator.
Stop Test Step 4. Check if the diagnostic code is still active.
A. Clean all contacts on the wiring harness connectors.
B. Reconnect all wiring harness connectors.
C. Turn the key start switch to the ON position and operate the machine.
D. Use Caterpillar Electronics Technician (Cat ET) Determine if the "CID 1251 FMI 03" diagnostic code exists.
Expected Result: The "CID 1251 FMI 03" diagnostic code exists.
Result: • Yes - The fault has not been eliminated. An ECM fault is unlikely.
Repair: Re-perform this diagnostic test procedure. If the cause of the diagnostic code is not found, the Product Link ECM should be replaced. Before replacing PL522 or 523, please contact your Caterpillar technical correspondent. Please refer to System Operation, Troubleshooting and Repair, Testing and Adjustment, "Electronic Control Module (ECM) - Replacement".
Stop • No - No diagnostic code exists. The fault does not exist at this time. The original fault may have been caused by a poor electrical connection or short circuit in a disconnected and reconnected wiring harness connector. Restore normal machine operation. Stop
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