How to diagnose and rule out MID 122 - CID 1251 - FMI 03 using 311B Excavator 2LS?

This code is generated in the following situation: 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.

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 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.

  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.

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 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.

 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. 

  • 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. 

 C. Turn the key start switch to the ON position and operate the machine. 

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".

 

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

 

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

 

Caterpillar 320E Excavator AWS Battery Troubleshooting

  Possible Causes 

• Charging Circuit 

• Battery 

• Auxiliary Devices 

Recommended Actions 

Follow the steps listed above in order. 

Troubleshooting and Testing Steps 

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1. Charging Circuit 

Result: Charging circuit malfunction. 

A. Check if the battery charging circuit is working properly. Refer to Troubleshooting, "Alternator Failure".

Repair: Repair the charging circuit if necessary.  

Result: Charging circuit is normal. Proceed to test step 2. 

2. Battery

A. Confirm that the battery can no longer hold its charge. Refer to System Operation/Testing and Adjustment, "Battery - Test".   

Result: One battery is malfunctioning. 

Repair: Replace the faulty battery. Refer to the Operation and Maintenance Manual. 

Result: Battery is normal. Proceed to test step 3.  

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3. Auxiliary Devices  

A. Check if the battery is being drained because the auxiliary device is constantly on. 

Result: The battery was drained because the auxiliary device was constantly on. 

Repair: Charge the battery. Verify that the battery can maintain its charge. Refer to system operation/testing and adjustment for the correct procedure. 

Result: The auxiliary device was constantly on, but the battery was not drained. 

  Please contact the Dealer Solutions Network (DSN).

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Caterpillar 311B Excavator 2LS Condensate Drain System Troubleshooting

To ensure the condensate drain hole is not clogged, it should be routinely inspected. Additionally, routine inspections are necessary to ensure a normal flow of condensate from the housing. When the air conditioning system is operating, condensate should be visible draining from the machine via the drain line.

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  • Inspect the drain line to ensure it is not compressed. 

 • Inspect the drain valve to ensure it is correctly installed. The drain valve should be between 0.0 mm (0.0 inch) and 76 mm (3 inches) from the drain pipe opening. 

 • If the drain line is clogged with dirt and debris, flush the drain line with water and reinstall the valve.

To ensure the drain system is functioning correctly, open the HVAC unit housing and inspect the sloping bottom or drain pan inside.  

  • Ensure there are no large debris clogging the drain valve inside the housing.

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• If large debris is found, clean the HVAC unit housing to prevent further accumulation and blockage of the drain path. • After cleaning the discharge area, reinstall the housing of the Heated Ventilation and Air Conditioning (HVAC) unit to ensure proper system operation. Run the system and check for condensate flow from the discharge pipe.

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How to resolve the low-speed engine stalling fault of a Caterpillar 320E Excavator AWS

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Possible Causes 

• Diagnostic Codes 

• Auxiliary Equipment

 • Power Mode Control (if equipped) 

• Fuel Supply 

• Low Compression (Cylinder Pressure)

 • Electronic Individual Injectors 

 Suggested Actions

  Note: The steps are listed below in order of probability. Perform these steps in sequence.

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  1. Diagnostic Codes 

A. Establish communication between the electronic repair tool and the electronic control module (ECM). If necessary, refer to Troubleshooting and Repair, "Electronic Repair Tools". 

 B. Check for any active or recorded codes.

 Diagnostic Codes

 Result: Code activated or recorded.

 Repair: Diagnose and eliminate all codes before proceeding to this step.

Result: Code not active or recorded. Proceed to test step 2. 

  2. Accessories

 A. Check all accessories for malfunctions that could place excessive load on the engine.

3. Power Mode Control (if equipped) 

 A. Check if the power mode control is using a CAT or CAN data link, and then perform appropriate testing. See Troubleshooting, "Data Link - Testing" or Troubleshooting, "CAN Data Link - Testing". 

 B. Check the engine wiring harness for defects. See Troubleshooting, "Electrical Connections - Inspection". 

Result: Faulty data link. Repair:

 Repair the data link if necessary. 

 Result: Faulty wiring. Repair: Repair or replace the wiring if necessary. 

Result: Data link and wiring are normal.  

Proceed to test step 4. 

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 4. Fuel Supply

 A. Ensure the vent hole on the fuel cap is not filled with debris. 

B. Ensure the fuel supply valve (if equipped) is in the fully open position. 

C. If the temperature is below 0 °C (32 °F), check the fuel for solidification (waxing).

  D. Check the fuel pre-filter/fuel-water separator for water. 

E. Check the fuel supply lines for blockages. F. Replace the in-line fuel filter installed upstream of the Electric Fuel Transfer Pump (EFLP). 

 G. Check that the EFLP is functioning properly. 

 H. Replace the fuel pre-filter and fuel fine filter. 

 I. Check for diesel fuel contamination. See System Operation, Testing and Adjustment, "Fuel Quality - Testing". 

 J. Check for air in the fuel system. See System Operation, Testing and Adjustment, "Air in Fuel - Testing".

Fuel System Result: Clogged vent in the fuel cap. 

   Repair: Install a replacement fuel cap. 

 Result: Fuel contains hardened wax. 

Repair: Replace with the correct fuel specification suitable for environmental conditions. 

 Result: Clogged fuel line. 

 Repair: Replace any damaged or clogged fuel lines.

EFLP may malfunction. See Troubleshooting and Repair, "Fuel Transfer Pump - Testing". 

Replace the fuel pre-filter and fuel fine filter. Please refer to the Operation and Maintenance Manual for more information.  

Result: Air is present in the fuel system.  

Repair: Charge the fuel system. Please refer to System Operation, Testing and Adjustment, "Fuel System - Charge". 

Result: Diesel fuel is contaminated. 

 Repair: Bleed the fuel tank and fuel system. 

 Replace the fuel pre-filter and fuel fine filter. Please refer to the Operation and Maintenance Manual for more information.   

Charge the fuel system with the correct specification fuel. Please refer to System Operation, Testing and Adjustment, "Fuel System - Charge". 

Result: Fuel supply is normal.  

Proceed to test step 5. 

5. Low Compression (Cylinder Pressure)  

A. Perform a compression test. Please refer to System Operation, Testing and Adjustment, "Compression - Test".  

Result: The compression test result exceeds technical specifications. Investigate the cause and troubleshoot any malfunctions. 

Note: Possible causes of low compression pressure are listed below: 

· Loose glow plug · Piston malfunction 

· Piston ring malfunction 

 · Bore wear 

 · Valve wear 

· Cylinder head gasket malfunction 

 · Cylinder head damage 

Result: Compression test result is normal.

Proceed to test step 6.  

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6. Electronic Individual Injector 

A. Perform an automatic "cylinder cut-off test" using electronic repair tools. 

Note: If the compression test performed in test step 5 meets expectations, the "cylinder cut-off test" will identify any faulty injectors. 

Result: Indicates a faulty injector. 

Repair: Remove any faulty electronic individual injector. See Disassembly and Assembly, "Electronic Individual Injector - Removal". 

  Install a new electronic individual injector. See Disassembly and Assembly, "Electronic Individual Injector - Installation".

 Repeat the automatic "cylinder cut-off test". If the fault remains obvious, remove the replacement electronic unit injector and install the original electronic unit injector. See Disassembly and Assembly, "Electronic Unit Injector - Removal" and Disassembly and Assembly, "Electronic Unit Injector - Assembly".

  Result: All injectors function correctly.

Please contact the Dealer Solutions Network (DSN). 

How to resolve the engine cranking timeout fault in a Caterpillar 320E Excavator AWS

  Possible Causes 

 • Diagnostic Codes

 • Starting Assist Devices 

 • Load • Battery

 • Charging Circuit 

• Starter Motor 

• Fuel Supply

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1. Check for Relevant Diagnostic Codes 

A. Establish communication between the electronic service tool and the ECM. If necessary, refer to Troubleshooting and Repair, "Electronic Service Tools". 

 B. Download the "Warranty Report" from the engine ECM before performing any troubleshooting or clearing diagnostic codes. 

Diagnose and eliminate all existing diagnostic codes before continuing this procedure.  

Diagnostic Codes 

Result: No active or recorded diagnostic codes. Proceed to Test Step 2.

Result: Code is active or recorded.  

Repair: Diagnose and eliminate the code before continuing this step. 

Refer to Troubleshooting and Repair, "Diagnostic Codes" for troubleshooting and eliminating diagnostic codes.

2. Starting Assist Device 

 A. If low-temperature conditions exist, check the operation of the starting assist device. 

 B. Confirm that the starting assist device is operating normally.   

Starting Assist Device

Result: The starting assist device is operating normally. Proceed to test step 3. 

 Result: The starting assist device is not operating normally. 

Repair: Refer to the corresponding circuit test for troubleshooting the starting assist device.   

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3. Overload 

A. Check for excessive load on the engine. 

 B. If necessary, disconnect the driven equipment and then test the engine again.  

Overload 

Result: The engine load is too high.

  Repair: Reduce the engine load. Return the unit to operation. 

 Result: There is no excessive load on the engine. Proceed to test step 4. 

4. Battery

 A. Check if the battery can maintain its charge. Refer to System Operation/Testing and Adjustment, "Battery - Test" for the correct procedures.  

  Battery

Result: The battery will not retain its charge. 

Repair: Replace the battery. Refer to the machine's disassembly and assembly manual for the correct procedures.  

Result: The battery retains its charge. 

  5. Switching the Battery Circuit

 A. Check the connections in the battery cables, wiring, and charging circuit. 

 B. Check the battery circuit discharge when in the ON position. 

 C. Charge the battery. Confirm that the battery can retain its charge.

6. Alternator 

 A. Check the condition of the alternator. For the correct procedures, refer to Troubleshooting and Repair, 

"Alternator Faults" 

Result: The alternator is functioning normally. Proceed to test step 7. 

Result: The alternator is not functioning normally.

Repair: Replace or repair the alternator.   

Battery Circuit 

  Result: The battery circuit is functioning normally. Proceed to test step 6.

Result: The battery circuit is not functioning normally. Repair: Clean and tighten all connections. Replace any faulty parts if necessary.

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Caterpillar 320E Excavator AWS Fuel Water Contamination Troubleshooting and Repair Test Procedure

 

 

 

 

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1. Drain the fuel-water separator cup. 

 A. Turn the ignition key to the off position. 

B. Drain the fuel-water separator cup. Refer to the Operation and Maintenance Manual, "Fuel System Coarse Filter/Fuel-Water Separator - Drain". 

 C. If necessary, charge the fuel system. Refer to the Operation and Maintenance Manual, "Fuel System - Charge".

  D. Turn the ignition key to the on position. Do not start the engine. Wait 1 minute. Fuel-water separator result: The "Fuel Water Contamination" warning disappears within 1 minute.

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  Proceed to Test Step 3.

  2. Confirm that the fuel is free of water.

 A. Run the engine for 5 minutes.

 Fuel Water Contamination

Result: The "Fuel Water Contamination" warning does not reappear within 5 minutes. 

  Return the unit to operation. 

Result: The "Water in Fuel" warning reappeared within 5 minutes. 

 Repair: The fuel supply is contaminated with water. Drain the fuel tank and then add clean fuel. 

Repeat the steps in step 1.

  If the problem persists, contact your Dealer Solution Network (DSN).

  3. Water in Fuel Switch 

A. Check the operation of the water in fuel switch. Refer to Troubleshooting and Repair, "Water in Fuel - Test".

 Water in Fuel Switch 

  Result: The water in fuel switch circuit requires repair. 

 Repeat the steps in step 1.

 Result: The water in fuel switch is working properly. 

 Repair: The fuel supply is contaminated with water. Drain the fuel tank and then add clean fuel. 

Repeat the steps in step 1.

  If the problem persists, contact your Dealer Solution Network (DSN).

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Troubleshooting Crankcase Vent Oil Injection in Caterpillar 320E Excavator AWS

  The crankcase vent filter cartridge includes a pressure relief valve to prevent excessive pressure buildup.

  Under normal engine operation, the pressure relief valve remains closed. If there is oil residue on the cylinder head behind the vent filter cartridge, perform the following steps to diagnose the problem.

 Possible Causes 

 • Breather Filter 

 • Vent Hose 

 • Excessive Blow-In 

 Recommended Actions

 

 

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Typical Vent Filter Cartridge

 (1) Breather Filter Canister Cap 

(2) Filter Element 

(3) Vent Filter Cartridge  

 

 Note: These steps are listed below in order of probability. Perform these steps in sequence.

 Troubleshooting and Troubleshooting Test Steps

   CAT Comm Adapter3 478-0235 Diagnostics for Caterpillar 

  1. Vent Filter

 A. Check the filter element

 (2) for proper installation and for any damage. B. Check the breather filter canister (3) for any obstructions or blockages.

 Note: In cold weather, the outlet of the respirator filter canister may freeze.

  Result: Filter element (2) is improperly installed or damaged. 

 Repair: Correctly install or replace the filter element. 

 Result: Respirator filter canister is clogged or blocked.

  Repair: Clean the inside of the respirator filter canister. 

 Result: The respirator is clean and functioning properly.

 2. Vent Hose 

 A. Ensure the return hose of the vent filter cartridge is not squeezed or blocked. 

B. Ensure the vent outlet hose of the vent filter cartridge is not squeezed or blocked.

Result:

 One or more hoses are squeezed or blocked. 

 Repair: Clean or replace the hose. 

Result: All hoses are clear. Proceed to test step 3.  

 3. Excessive Blow-In 

Note: Excessive blow-in increases the amount of smoke flowing through the respirator system, leading to filter clogging. The pressure relief valve may subsequently open.

  A. Check the engine for excessive blow-by. 

 Result: Excessive blow-by. 

 Repair: Replace the breather filter.

 Investigate the cause of the excessive blow-by. Please refer to Troubleshooting and Repair, "Excessive Oil Consumption".

  Result: Blow-by is not excessive. 

Please contact the Dealer Solutions Network (DSN).

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