How to handle the Caterpillar 311B Excavator 2LS MID161-CID1251-FMI03 fault

 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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How to diagnose and troubleshoot the Caterpillar 311B Excavator MID 161 - CID 0168 - FMI 01 fault message?

 This code is generated when PL522 and 523 detect a battery voltage below 11 VDC.

 

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 Test Step 1. Check the system voltage at the 70-pin connector of the PL522 and 523 modules.

  Start the engine and run it at high idle for 5 to 10 minutes. Measure the system voltage between the "No Switching Power" and "Ground" contacts. Pin 52 is the "No Switching Power" terminal, and pin 65 is the "Ground" terminal.

  Expected Results: 24 VDC system voltage: 27 VDC to 29 VDC. 12 VDC system voltage: 13 VDC to 15 VDC. Results:

  • Normal - Voltage is correct. Clear this diagnostic code and check for any other diagnostic codes. Stop.

 • Abnormal - The voltage is abnormal. Proceed to Test Step 2.

 Test Step 2. Check the alternator.

  Run the engine at high idle for 5 to 10 minutes. Measure the voltage output at the battery terminals.

 Expected Result: For a 24 VDC system, the voltage range should be 27 VDC to 29 VDC. For a 12 VDC system, the voltage range should be 13 VDC to 15 VDC.

 

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  Result: • Normal - Voltage is correct. Proceed to Test Step 3.

 • Abnormal - The voltage is abnormal.

  Repair: Repair or replace the alternator.

 Stop Test Step 3. Check the battery voltage.

  Turn the ignition switch to the off position. Measure the voltage at the battery terminals. Always wear appropriate personal protective equipment. Expected Result: For a 12 VDC system, the voltage should be 12 VDC to 15 VDC. For a 24 VDC system, the voltage should be 24 VDC to 27 VDC.

  Results:

 • Normal - Voltage between 12 VDC and 15 VDC, or between 24 VDC and 27 VDC.

 Repair: PL522 or 523 may be faulty. Recheck the system before replacing PL522 or 523. PL522 or 523 are rarely the root cause of the problem. Refer to System Operation, Troubleshooting and Repair, Testing and Adjustment, "Electronic Control Module (ECM) - Replacement". After replacing PL522 or 523, recheck the system and check the status of diagnostic codes.

 Stop • Abnormal - Voltage not between 12 VDC and 15 VDC, or between 24 VDC and 27 VDC.

  Repair: Refer to the specific manual, REHS0354, "Charging System Troubleshooting and Repair". If the situation does not improve, PL522 or 523 may be faulty. Recheck the system before replacing PL522 or 523. PL522 or 523 are rarely the root cause of the problem. Please refer to System Operation, Troubleshooting and Troubleshooting, Testing and Adjustment, "Electronic Control Module (ECM) - Replacement". After replacing PL522 or 523, recheck the system and check the status of diagnostic codes.

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How to diagnose and troubleshoot the Caterpillar 311B Excavator MID 161 - CID 0168 - FMI 00 fault message?

     

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 This code is generated when: 

 The diagnostic circuitry within PL522 and 523 detects a system voltage higher than 32 VDC.

Possible causes of this fault include: 

• A faulty charging system component. 

• A faulty wiring harness conductor. 

• A faulty PL522 or 523. A module fault is unlikely.  

Note: Determine if a battery charger or welding machine is being used on the machine. Disconnect the charger or welding machine from the machine. Recheck for diagnostic codes.

  Test Procedure 1. Check the system voltage at the 70-pin connector of PL522 or 523.

  A. Start the engine and run it at high idle for 5 to 10 minutes.

  B. Measure the system voltage between the "No Switching Power" and "Ground" contacts. Pin 52 is the "No Switching Power" terminal, and pin 65 is the "Ground" terminal.

  Expected Result: Voltage is 11 VDC to 32 VDC.

 Result: • Normal - Voltage is 11 VDC to 32 VDC. PL522 or 523 should not record this diagnostic code.

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  Repair: Clear the diagnostic code from PL522 or 523 using a Caterpillar Electronics Technician (Cat ET). If the voltage is normal and PL522 or 523 records this diagnostic code again, replace PL522 or 523. Before replacing PL522 or 523, please contact your Caterpillar technical communicator. 

 

 Stop • Abnormal - Voltage is not 11 VDC to 32 VDC. Proceed to Test Step 2. 

Test Step 2. Check the alternator. 

 A. Run the engine at high idle for 5 to 10 minutes. 

 B. Measure the voltage output at the battery terminals.  

  Expected result: The voltage should be below 32 VDC.

  Result: • Normal - Voltage below 32 VDC. The battery may be faulty. Proceed to test step 3. 

  • Abnormal - Voltage above 32 VDC. Troubleshoot the alternator. The voltage regulator may be faulty. If no issues are resolved, proceed to test step 3.

 Test Step 3. Check the battery voltage.

 Turn the ignition switch to the off position. Measure the voltage at the battery terminals.

 Expected result: The voltage should be below 32 VDC.

  Result: • Normal - Voltage below 32 VDC. Proceed to test step 4.

 

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  • Abnormal - Voltage above 32 VDC.

Repair: Refer to the specific instruction manual, REHS0354, "Charging System Troubleshooting".  

  If no issues are resolved, proceed to test step 4.

 

  Test Step 4. Check each ECM on the machine.

 

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  Check the recorded diagnostic codes of other ECMs installed on the machine. Compare each ECM that recorded the "CID 168 FMI 00" code within the same time period. The Hourly Meter Hours (SMH) on the logs may differ. The difference between the current SMH and the recorded SMH is critical.

 

  Expected Result: Other "CID 168 FMI 00" diagnostic codes can be found on other Electronic Control Modules (ECMs).

 

 Result: • Yes - Other "CID 168 FMI 00" diagnostic codes can be found on other Electronic Control Modules (ECMs). Repair: Clear the fault if all of the following occur:

 

  ◦ No fault was found in the charging system. 

 ◦ No fault was found in the wiring.

  ◦ The fault recurred several times.

 Monitor the module and the machine for any further faults. If the fault recurs, the PL522 or 523 module is likely not faulty because other ECMs are displaying the same fault. Recheck the system voltage.

  Stop • No - No other "CID 168 FMI 00" diagnostic codes can be found on other ECMs. Repair: Clear the fault if all of the following occur: 

◦ No fault was found in the charging system. 

◦ No fault was found in the wiring. 

 ◦ The fault has recurred several times.

 

  Monitor the module and machine for further faults. If the fault recurs, the PL522 or 523 module may be faulty. The PL522 or 523 should be replaced. Refer to System Operation, Troubleshooting & Repair, Testing & Adjustment, "Electronic Control Module (ECM) - Replacement". After replacing the PL522 or 523, recheck the system and the status of the diagnostic codes.

  

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How to diagnose and troubleshoot the Caterpillar 311B Excavator MID 122 - CID 1251 - FMI 03 fault message?

 

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 This code is generated in the following situations:

The Product Link module tracks machine operating hours and reports them 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. If the input continuously receives voltage signals above the normal value, the reported timekeeping hours (SMU) will be inaccurate. 

Test Procedure 1. Check for a short circuit between the R-terminal cable and the battery.

A. Disconnect the Product Link cable (P1) from the Product Link module.   

 

 B. Measure the resistance from alternator R-terminal input J1-4 (403MC9-GN-18) to battery (J1-1). Expected result: The resistance should be greater than 5000 ohms.

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Result: 

• OK - The Product Link harness appears to be normal. Proceed to test step 2.

• Abnormal - The Product Link cable may be short-circuited to the battery. 

  Repair: Repair the cable and confirm the fault has been eliminated.

  Stop Test Step 2. Check for short circuits between the PRODUCT LINK harness and the voltage source. 

 A. Disconnect the Product Link cable (P1) from the Product Link module.

  B. Start the engine.

 C. Confirm the presence of a 0 kHz to 2 kHz 11 VDC to 32 VDC square wave by measuring the alternator R-terminal input (J1-4). Additionally, a stable DC voltage equivalent to the battery voltage should be present.

  Expected result: No stable voltage equivalent to the battery voltage was measured when measuring the alternator R-terminal input. DC voltage.

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 Result: • OK - The signal is a 0 kHz to 2 kHz 11 VDC to 32 VDC square wave or a stable DC voltage equivalent to the battery. The Product Link harness may not be faulty. Proceed to Test Step 3.

• Abnormal - The Product Link cable may be short-circuited to a DC voltage other than the battery voltage. Repair: Repair the cable and confirm the fault has been eliminated. 

  Stop Test Step 3. Check the machine alternator. 

A. Disconnect the Product Link machine cable from the alternator. 

  B. Start the engine.

 C. Measure the alternator R terminal to confirm the presence of a 0 kHz to 2 kHz 11 VDC to 32 VDC square wave. There should be no stable DC voltage equivalent to the battery voltage.

  Expected Result: There should be a 0 kHz to 2 kHz 11 VDC to 32 VDC square wave at the alternator R terminal.

 

 Result: • OK - There is a square wave at the alternator R terminal. 0 kHz to 2 kHz 11 VDC to 32 VDC square wave. Proceed to Test Step 4. 

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  • Abnormal - No 0 kHz to 2 kHz 11 VDC to 32 VDC square wave 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.

  D. Use a Caterpillar Electronics Technician (Cat ET) to determine if the "CID 1251 FMI 03" diagnostic code is present. Expected Result: The "CID 1251 FMI 03" diagnostic code is present.

 Result: • Yes - This fault has not been resolved. The ECM is unlikely to be faulty.

 

 Repair: Re-perform this diagnostic test step. If the cause of this diagnostic code cannot be found, the Product Link ECM should be replaced. Before replacing the Product Link, please contact your Caterpillar technical correspondent. Please refer to System Operation, Troubleshooting & Repair, Testing & Adjustment, "Electronic Control Module (ECM) - Replacement".

 

Caterpillar diagnostic “T-connector” communication wiring or “Y-type” diagnostic harness

 

Stop • No - No diagnostic code found. The fault does not exist at this time. The initial problem may have been caused by a poor electrical connection or short circuit when disconnecting and reconnecting a wiring harness connector. Restore the machine to normal operation. Stop

 

 

 

 

 

 

  

How to diagnose and troubleshoot the Caterpillar 311B Excavator MID 161 - CID 0168 - FMI 01 fault message?

                                         

                       MID 161 - CID 0168 - FMI 01

 

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 This code is generated when PL522 and 523 detect a battery voltage below 11 VDC.

  Test Procedure 1. Check the system voltage at the 70-pin connector of the PL522 and 523 modules.

  Start the engine and run it at high idle for 5 to 10 minutes. Measure the system voltage between the "No Switching Power" and "Ground" contacts. Pin 52 is the "No Switching Power" terminal, and pin 65 is the "Ground" terminal.

  Expected Results: 24 VDC system voltage: 27 VDC to 29 VDC. 12 VDC system voltage: 13 VDC to 15 VDC. Results:

  • Normal - Voltage is correct. Clear this diagnostic code and check for any other diagnostic codes. Stop

 • Abnormal - The voltage is abnormal. Proceed to Test Step 2. 

 Test Step 2. Check the alternator.

 Run the engine at high idle for 5 to 10 minutes. Measure the voltage output at the battery terminals.

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 Expected Result: For a 24 VDC system, the voltage range should be 27 VDC to 29 VDC. For a 12 VDC system, the voltage range should be 13 VDC to 15 VDC.

  Result: 

• Normal - The voltage is correct. Proceed to Test Step 3

. • Abnormal - The voltage is abnormal.

  Repair: Repair or replace the alternator.

 

  Stop Test Step 3. Check the battery voltage.

  Turn the ignition switch to the off position. Measure the voltage at the battery terminals. Always wear appropriate personal protective equipment. Expected Result: The voltage of a 12 VDC system should be between 12 VDC and 15 VDC. The voltage of a 24 VDC system should be between 24 VDC and 27 VDC.

  Result: • Normal - Voltage between 12 VDC and 15 VDC, or between 24 VDC and 27 VDC.

  Repair: PL522 or 523 may be faulty. Recheck the system before replacing PL522 or 523. PL522 or 523 are rarely the root cause of failure. Please refer to System Operation, Troubleshooting and Repair, Testing and Adjustment, "Electronic Control Module (ECM) - Replacement". After replacing PL522 or 523, recheck the system and check the status of diagnostic codes.

 Stop • Abnormal - Voltage is not between 12 VDC and 15 VDC, or voltage is not between 24 VDC and 27 VDC.

  Repair: Refer to the specific manual, REHS0354, "Charging System Troubleshooting and Repair". If the situation does not improve, PL522 or 523 may be faulty. Recheck the system before replacing PL522 or 523. PL522 or 523 are rarely the root cause of the problem. Refer to System Operation, Troubleshooting and Repair, Testing and Adjustment, "Electronic Control Module (ECM) - Replacement". After replacing PL522 or 523, recheck the system and check the status of diagnostic codes.

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