Cummins/Onan QSF3.8 CM2350 F107 troubleshooting: 2 fault codes and 195 symptom-cause-remedy entries from the manufacturer's own service documentation.
Cummins/Onan QSF3.8 CM2350 F107 — full specs, parts & maintenance.
All Cummins/Onan fault codes →
| Code | Meaning | Remedy |
|---|---|---|
| 400040 | Wait-to-Start | Wait for the Wait-to-Start lamp to turn off before starting the engine |
| 11000252 | Low Oil Pressure | Shut off the engine immediately to avoid damage |
| Symptom | Cause | Remedy |
|---|---|---|
| Charging System Alternator Not Charging or Insufficient Charging | Alternator pulley is loose on the shaft | Tighten the pulley. Refer to equipment manufacturer service information. |
| Charging System Alternator Not Charging or Insufficient Charging | Batteries have malfunctioned | Check the condition of the batteries. Replace the batteries, if necessary. Refer to equipment manufacturer service information. |
| Charging System Alternator Not Charging or Insufficient Charging | Battery cables or connections are loose, broken, or corroded (excessive resistance) | Check the battery cables and connections. |
| Charging System Alternator Not Charging or Insufficient Charging | Alternator is overloaded, or alternator capacity is below specification | Install an alternator with a higher capacity. Refer to equipment manufacturer service information. |
| Charging System Alternator Not Charging or Insufficient Charging | Alternator or voltage regulator is malfunctioning | Test the alternator output. Replace the alternator or voltage regulator, if necessary. Refer to equipment manufacturer service information. |
| Charging System Alternator Not Charging or Insufficient Charging | Battery temperature is above specification | Position the batteries away from heat sources. Refer to equipment manufacturer service information. |
| Charging System Alternator Not Charging or Insufficient Charging | Electrical system is "open" (blown fuses, broken wires, or loose connections) | Check the fuses, wires, and connections. Refer to equipment manufacturer service information. |
| Charging System Alternator Not Charging or Insufficient Charging | Vehicle gauge is malfunctioning | Check the vehicle gauge. Refer to equipment manufacturer service information. |
| Charging System Alternator Overcharging | Batteries have failed | Check the condition of the batteries. Replace the batteries, if necessary. Refer to equipment manufacturer service information. |
| Charging System Alternator Overcharging | Voltage regulator is malfunctioning | Check the voltage regulator. Replace the voltage regulator, if necessary. Refer to equipment manufacturer service information. |
| Coolant Contamination | Coolant is rusty and has debris | Drain and flush the cooling system. Fill with the correct mixture of antifreeze and water. Refer to Procedure 008-018 in Section 7. |
| Coolant Contamination | Transmission oil cooler or torque converter cooler is leaking | If applicable, check the transmission oil cooler and torque converter cooler for coolant leaks. Refer to equipment manufacturer service information. |
| Coolant Contamination | Lubricating oil cooler is leaking | Check the lubricating oil cooler for coolant leaks and cracks. Refer to a Cummins® Authorized Repair Location. |
| Coolant Contamination | Cylinder head gasket is leaking | Check the cylinder head gasket. |
| Coolant Loss - External | Coolant level is below specification | Check the coolant level. Check for an external leak. Refer to equipment manufacturer service information. Sample the lubricating oil and have a laboratory check for coolant in the oil (internal leak). |
| Coolant Loss - External | External coolant leak | Inspect the engine for coolant leaking externally from items such as coolant hoses, drain valves, coolant manifolds, expansion and pipe plugs, fittings, exhaust gas recirculation cooler coolant lines, turbocharger, coolant lines, transmission oil cooler or torque converter oil cooler, water pump seal, radiator core, heat exchanger, lubricating oil cooler housing, aftertreatment diesel exhaust fluid tank heater and hoses, aftertreatment diesel exhaust fluid dosing valve coolant lines, and original equipment manufacturer mounted components that have coolant flow. If necessary, pressure test the cooling system. Refer to Procedure 008-018 in Section 7. |
| Coolant Loss - External | Radiator cap is not correct, is malfunctioning, or has low-pressure rating | Check the radiator pressure cap. Refer to equipment manufacturer service information. |
| Coolant Loss - External | Cooling system hose is collapsed, restricted, or leaking | Inspect the hoses. Refer to Procedure 008-045 in Section 7. |
| Coolant Loss - External | Coolant fill line is restricted or obstructed | Check the coolant fill line for restrictions or obstructions. Refer to Procedure 008-018 in Section 7. |
| Coolant Loss - External | Coolant is rusty and has debris | Drain and flush the cooling system. Fill with the correct mixture of antifreeze and water. Refer to Procedure 008-018 in Section 7. |
| Coolant Loss - External | Engine is overheating | Refer to the Coolant Temperature is Above Normal - Sudden Overheat or the Coolant Temperature is Above Normal - Gradual Overheat troubleshooting symptom tree in Section TS. |
| Coolant Temperature Above Normal - Gradual Overheat | Charge-air cooler fins, radiator fins, or air conditioner condenser fins are damaged or obstructed with debris | Inspect the charge-air cooler, air conditioner condenser, and radiator fins. Clean, if necessary. Refer to Procedure 010-027 in Section 4 and see equipment manufacturer service information. |
| Coolant Temperature Above Normal - Gradual Overheat | Cold weather radiator cover or winterfront is closed | Open the cold weather radiator cover or the winterfront. Maintain a minimum of 387 cm²[60 in²] of opening at all times. Refer to Procedure 101-015 in Section 1. |
| Coolant Temperature Above Normal - Gradual Overheat | Coolant level is below specification | Check the coolant level. Check for an external leak. Refer to Procedure 008-066 in Section 3. Sample the lubricating oil and have a laboratory check for coolant in the oil (internal leak). |
| Coolant Temperature Above Normal - Gradual Overheat | Electronic fault codes are active or high counts of inactive fault codes | Review instructions for reading active fault codes. |
| Coolant Temperature Above Normal - Gradual Overheat | Fan shroud is damaged or missing or the air recirculation baffles are damaged or missing | Inspect the shroud and the recirculation baffles. Repair, replace, or install, as necessary. Refer to Procedure 101-007 in Section 1. |
| Coolant Temperature Above Normal - Gradual Overheat | Lubricating oil is contaminated with coolant or fuel | Refer to the Lubricating Oil Contaminated symptom tree in Section TS. |
| Coolant Temperature Above Normal - Gradual Overheat | Cooling system hose is collapsed, restricted, or leaking | Inspect the hoses. Refer to Procedure 008-045 in Section 7. |
| Coolant Temperature Above Normal - Gradual Overheat | Coolant mixture of antifreeze and water is not correct | Verify the concentration of antifreeze in the coolant. Add antifreeze or water to correct the concentration. Refer to Procedure 008-018 in Section 7 and Procedure 018-004 in Section V. |
| Coolant Temperature Above Normal - Gradual Overheat | Lubricating oil level is above or below specification | Check the oil level. Add or drain oil, if necessary. Refer to Procedure 007-043 in Section 3 and Procedure 018-003 in Section V. |
| Coolant Temperature Above Normal - Gradual Overheat | Coolant temperature gauge is malfunctioning | Test the temperature gauge. Repair or replace the gauge, if necessary. Contact a Cummins® Authorized Repair Location. |
| Coolant Temperature Above Normal - Gradual Overheat | Fan drive belt is loose, tight, or not in alignment | Check the fan drive belt. Refer to Procedure 008-087 in Section 7. |
| Coolant Temperature Above Normal - Gradual Overheat | Vehicle cooling system is not adequate | Verify that the engine and vehicle cooling systems are using the correct components. Refer to equipment manufacturer service information. |
| Coolant Temperature Above Normal - Sudden Overheat | Coolant level is below specification | Check the coolant level. Check for an external leak. Refer to Procedure 008-066 in Section 3. Sample the lubricating oil and have a laboratory check for coolant in the oil (internal leak). |
| Coolant Temperature Above Normal - Sudden Overheat | Electronic fault codes are active or high counts of inactive fault codes | Review instructions for reading active fault codes. |
| Coolant Temperature Above Normal - Sudden Overheat | Air in the cooling system | Inspect and vent the cooling system. Refer to Procedure 008-018 in Section 7. |
| Coolant Temperature Above Normal - Sudden Overheat | Fan drive belt is broken | Check the fan drive belt. Replace the belt, if necessary. Refer to Procedure 008-002 in Section 7. |
| Coolant Temperature Above Normal - Sudden Overheat | Radiator cap is not correct, is malfunctioning, or has low-pressure rating | Check the radiator pressure cap. Refer to equipment manufacturer service information. |
| Coolant Temperature Above Normal - Sudden Overheat | Cooling system hose is collapsed, restricted, or leaking | Inspect the hoses. Refer to Procedure 008-045 in Section 7. |
| Coolant Temperature Above Normal - Sudden Overheat | Coolant temperature gauge is malfunctioning | Test the temperature gauge. Repair or replace the gauge, if necessary. Contact a Cummins® Authorized Repair Location. |
| Coolant Temperature Above Normal - Sudden Overheat | Charge-air cooler fins, radiator fins, or air conditioner condenser fins are damaged or obstructed with debris | Inspect the charge-air cooler, air conditioner condenser, and radiator fins. Clean, if necessary. Refer to Procedure 010-027 in Section 4 and equipment manufacturer service information. |
| Coolant Temperature Above Normal - Sudden Overheat | Cold weather radiator cover or winterfront is closed | Open the cold weather radiator cover or the winterfront. Maintain a minimum of 387 cm²[60 in²] of opening at all times. Refer to Procedure 101-015 in Section 1. |
| Coolant Temperature Below Normal | Coolant temperature gauge or sensor is malfunctioning | Test the gauge or the sensor. Repair or replace, if necessary. Refer to equipment manufacturer service information. |
| Coolant Temperature Below Normal | Electronic fault codes are active or high counts of inactive fault codes | Review instructions for reading active fault codes. |
| Coolant Temperature Below Normal | Engine is operating at low ambient temperature | Check the winterfront, shutters, and under-the-hood air. Use under-the-hood intake air in cold weather. Refer to the following bulletin, Cold Weather Operation, Bulletin 3387266. Refer to Procedure 101-015 in Section 1. |
| Coolant Temperature Below Normal | Fan drive or fan controls are malfunctioning | Check the fan drive and controls. Contact a Cummins® Authorized Repair Location. |
| Coolant Temperature Below Normal | Coolant temperature gauge is malfunctioning | Test the temperature gauge. Repair or replace the gauge, if necessary. Contact a Cummins® Authorized Repair Location. |
| Coolant Temperature Below Normal | Thermostat is not correct or is malfunctioning | Check the thermostat for the correct part number and for correct operation. |
| Engine Acceleration or Response Poor | Operator technique is not correct | Refer to Procedure 101-014 in Section 1. |
| Engine Acceleration or Response Poor | Fuel level is low in the tank | Fill the supply tank. Refer to equipment manufacturer service information. |
| Engine Acceleration or Response Poor | Vehicle parasitics are excessive | Check the vehicle for brakes dragging, transmission malfunction, cooling fan operation cycle time, and engine-driven units. Refer to equipment manufacturer service information. |
| Engine Acceleration or Response Poor | Clutch is malfunctioning or is not correct | Compare the drivetrain specifications to Cummins Inc. recommendations. Check the clutch for correct operation. Refer to equipment manufacturer service information. |
| Engine Acceleration or Response Poor | Drivetrain is not correctly matched to the engine | Check for correct gearing and drivetrain components. Refer to equipment manufacturer service information. |
| Engine Acceleration or Response Poor | Electronic fault codes are active or high counts of inactive fault codes | Review instructions for reading active fault codes. |
| Engine Acceleration or Response Poor | Fuel leak | Check the fuel lines, fuel connections, and fuel filters for leaks. Check the fuel lines to the supply tanks. Refer to equipment manufacturer service information. |
| Engine Acceleration or Response Poor | Intake manifold air temperature is above specification | Refer to the Intake Manifold Air Temperature Above Specification symptom tree in Section TS. |
| Engine Acceleration or Response Poor | Charge-air cooler is restricted or leaking | Inspect the charge-air cooler for air restrictions or leaks. Refer to Procedure 010-027 in Section 4. |
| Engine Acceleration or Response Poor | Air in the fuel system | Check for air in the fuel system. Tighten or replace the fuel connections, fuel lines, fuel tank standpipe, and fuel filters as necessary. |
| Engine Acceleration or Response Poor | Air intake or exhaust leaks | Check for loose or damaged piping connections and missing pipe plugs. Check the turbocharger and exhaust manifold mounting. Refer to Procedure 010-058 in Section 3. |
| Engine Acceleration or Response Poor | Air intake system restriction is above specification | Check the air intake system for restriction. Replace the air cleaner element, if necessary. |
| Engine Acceleration or Response Poor | Fuel grade is not correct for the application or the fuel quality is poor | Operate the engine from a tank of known high quality fuel. Refer to Procedure 018-002 in Section V. |
| Engine Acceleration or Response Poor | Fuel filter or fuel suction line is restricted | Replace the fuel filter. Check the fuel suction line for restriction. Refer to Procedure 006-015 in Section 5. |
| Engine Acceleration or Response Poor | Fuel supply is not adequate | Check the flow through the filter to locate the source of the restriction. Refer to Procedure 006-015 in Section 5. |
| Engine Difficult to Start or Will Not Start (Exhaust Smoke) | Starting procedure is not correct | Verify the correct starting procedure. Refer to Procedure 101-014 in Section 1. |
| Engine Difficult to Start or Will Not Start (Exhaust Smoke) | Fuel level is low in the tank | Fill the supply tank. Refer to equipment manufacturer service information. |
| Engine Difficult to Start or Will Not Start (Exhaust Smoke) | Electronic fault codes are active or high counts of inactive fault codes | Review instructions for reading active fault codes. |
| Engine Difficult to Start or Will Not Start (Exhaust Smoke) | Starting aid, if necessary for cold weather, is malfunctioning | Check for correct operation of the cold weather starting aid. Refer to Procedure 101-004 in Section 1 or the manufacturer's instructions. |
| Engine Difficult to Start or Will Not Start (Exhaust Smoke) | Engine block heater is malfunctioning, if equipped | Check the electrical sources and wiring to the cylinder block heater. Replace the block heater, if necessary. Refer to equipment manufacturer service information. |
| Engine Difficult to Start or Will Not Start (Exhaust Smoke) | Fuel heater is malfunctioning, if equipped | Check the fuel heater and replace, if necessary. Refer to equipment manufacturer service information. |
| Engine Difficult to Start or Will Not Start (Exhaust Smoke) | Battery voltage is low | Check the batteries and the unswitched battery supply circuit. Refer to equipment manufacturer service information. |
| Engine Difficult to Start or Will Not Start (Exhaust Smoke) | Keyswitch circuit is malfunctioning | |
| Engine Difficult to Start or Will Not Start (Exhaust Smoke) | Vehicle parasitics are excessive | Check the vehicle for brakes dragging, transmission malfunction, cooling fan operation cycle time, and engine-driven units. Refer to equipment manufacturer service information. |
| Engine Difficult to Start or Will Not Start (Exhaust Smoke) | Air in the fuel system | Check the fuel lines, fuel connections, and fuel filters for leaks. Check the fuel lines to the supply tanks. Refer to equipment manufacturer service information. |
| Engine Difficult to Start or Will Not Start (Exhaust Smoke) | Fuel leak | Check the fuel lines, fuel connections, and fuel filters for leaks. Check the fuel lines to the supply tanks. Refer to equipment manufacturer service information. |
| Engine Difficult to Start or Will Not Start (Exhaust Smoke) | Air intake system restriction is above specification | Check the air intake system for restriction. Replace the air filter and inlet piping as necessary. Refer to Procedure 010-059 in Section 3. |
| Engine Difficult to Start or Will Not Start (Exhaust Smoke) | Fuel grade is not correct for the application or the fuel quality is poor | Operate the engine from a tank of known high quality fuel. Refer to Procedure 018-002 in Section V. |
| Engine Difficult to Start or Will Not Start (Exhaust Smoke) | Fuel filter or fuel suction line is restricted | Replace the fuel filter. Check the fuel suction line for restriction. Refer to Procedure 006-015 in Section 5. |
| Engine Difficult to Start or Will Not Start (Exhaust Smoke) | Fuel supply is not adequate | Check the flow through the filter to locate the source of the restriction. Refer to Procedure 006-015 in Section 5. |
| Engine Difficult to Start or Will Not Start (No Exhaust Smoke) | Fuel level is low in the tank | Verify the correct starting procedure. Refer to Procedure 101-014 in Section 1. |
| Engine Difficult to Start or Will Not Start (No Exhaust Smoke) | Starting procedure is not correct | Verify the correct starting procedure. Refer to Procedure 101-014 in Section 1. |
| Engine Difficult to Start or Will Not Start (No Exhaust Smoke) | Fuel grade is not correct for the application or the fuel quality is poor | Operate the engine from a tank of known high quality fuel. Refer to Procedure 018-002 in Section V. |
| Engine Difficult to Start or Will Not Start (No Exhaust Smoke) | Electronic fault codes are active or high counts of inactive fault codes | Review instructions for reading active fault codes. |
| Engine Difficult to Start or Will Not Start (No Exhaust Smoke) | Original equipment manufacturer (OEM) engine protection system is malfunctioning | Isolate the OEM engine protection system. Follow the OEM service manual instructions to check for a malfunction. |
| Engine Difficult to Start or Will Not Start (No Exhaust Smoke) | Battery voltage is low | Check the batteries and the unswitched battery supply circuit. Refer to equipment manufacturer service information. |
| Engine Difficult to Start or Will Not Start (No Exhaust Smoke) | Keyswitch circuit is malfunctioning | Check the vehicle, equipment, or vessel keyswitch circuit. Refer to a Cummins® Authorized Repair Location. |
| Engine Difficult to Start or Will Not Start (No Exhaust Smoke) | Battery supply to the engine control module (ECM) is low, interrupted, or open | Check the battery connections, fuses, and unswitched battery supply circuit. Refer to equipment manufacturer service information. |
| Engine Difficult to Start or Will Not Start (No Exhaust Smoke) | Moisture in the wiring harness connectors | Dry the connector with Cummins® electrical contact cleaner, Part Number 3824510. Refer to equipment manufacturer service information. |
| Engine Difficult to Start or Will Not Start (No Exhaust Smoke) | Air in the fuel system | Check for air in the fuel system. Tighten or replace the fuel connections, fuel lines, fuel tank standpipe, and fuel filters as necessary. |
| Engine Difficult to Start or Will Not Start (No Exhaust Smoke) | Engine control module (ECM) is locked up | Disconnect the battery cables for 30 seconds. Connect the battery cables and start the engine. |
| Engine Difficult to Start or Will Not Start (No Exhaust Smoke) | Fuel filter or fuel suction line is restricted | Replace the fuel filter. Check the fuel suction line for restriction. Refer to Procedure 006-015 Section 5. |
| Engine Difficult to Start or Will Not Start (No Exhaust Smoke) | Fuel supply is not adequate | Check the flow through the filter to locate the source of the restriction. Refer to Procedure 006-015 Section 5. |
| Engine Difficult to Start or Will Not Start (No Exhaust Smoke) | Fuel drain backup | Verify the fuel return line is plumbed to the bottom of the fuel tank. |
| Engine Noise Excessive | Fan drive belt is loose, tight, or not in alignment | Check the fan drive belt. Refer to Procedure 008-087 in Section 5. |
| Engine Noise Excessive | Lubricating oil is thin or diluted | Refer to Procedure 018-003 in Section V. If the oil pressure is low, refer to the Lubricating Oil Pressure Low troubleshooting symptom tree in Section TS. |
| Engine Noise Excessive | Crankshaft pulley is damaged | Inspect the crankshaft pulley. |
| Engine Noise Excessive | Air intake or exhaust leaks | Check for loose or damaged piping connections and missing pipe plugs. Check the turbocharger and exhaust manifold mounting. Refer to Procedure 010-058 in Section 3. |
| Engine Noise Excessive | Air intake or exhaust piping is contacting the chassis or cab | Inspect the air piping, chassis, and cab for contact points. Refer to equipment manufacturer service information. |
| Engine Noise Excessive | Air intake system restriction is above specification | Check the air intake system for restriction. Replace the air filter and inlet piping as necessary. Refer to Procedure 010-059 in Section 3. |
| Engine Noise Excessive | Coolant temperature is above specification | Refer to the Coolant Temperature is Above Normal - Sudden Overheat or the Coolant Temperature is Above Normal - Gradual Overheat symptom tree in Section TS. |
| Engine Noise Excessive | Engine mounts are worn, damaged, or not correct | Check the engine mounts. Refer to equipment manufacturer service information. |
| Engine Noise Excessive | Fan clutch, hydraulic pump, or refrigerant compressor noise is excessive | Isolate each component and check for noise. Refer to equipment manufacturer service information. |
| Engine Noise Excessive | Fan is loose, damaged, or has excessive hub bearing end clearance | Check the fan. Refer to Procedure 008-087 in Section 5. |
| Engine Noise Excessive - Combustion Knocks | Engine is operating at low ambient temperature | Check the winterfront, shutters, and under-the-hood air. Use under-the-hood intake air in cold weather. Refer to Procedure 101-015 in Section 1. |
| Engine Noise Excessive - Combustion Knocks | Fuel grade is not correct for the application or the fuel quality is poor | Operate the engine from a tank of known high quality fuel. Refer to Procedure 048-002 in Section V. |
| Engine Noise Excessive - Combustion Knocks | Air in the fuel system | Check for air in the fuel system. Tighten or replace the fuel connections, fuel lines, fuel tank standpipe, and fuel filters as necessary. |
| Engine Noise Excessive - Combustion Knocks | Coolant temperature is below specification | Refer to the Coolant Temperature Below Normal troubleshooting symptom tree in Section TS. |
| Engine Power Output Low | Electronic fault codes are active or high counts of inactive fault codes | Review instructions for reading active fault codes. |
| Engine Power Output Low | Fuel grade is not correct for the application or the fuel quality is poor | Operate the engine from a tank of known high quality fuel. Refer to Procedure 018-002 in Section V. |
| Engine Power Output Low | Engine is operating above recommended altitude | Engine power decreases above recommended altitude. Refer to equipment manufacturer service information. |
| Engine Power Output Low | Tachometer is not calibrated or is malfunctioning | Compare the tachometer reading with a handheld tachometer or an electronic service tool reading. Calibrate or replace the tachometer as necessary. Refer to equipment manufacturer service information. |
| Engine Power Output Low | Intake and exhaust system restricted | Check the intake and exhaust systems for restrictions. Inspect the intake air filter and replace as necessary. Refer to Procedure 010-059 in Section 3. |
| Engine Power Output Low | Air intake system restriction is above specification | Check the air intake system for restriction. Replace the air filter and inlet piping as necessary. Refer to Procedure 010-059 in Section 3. |
| Engine Power Output Low | Air intake or exhaust leaks | Check for loose or damaged piping connections and missing pipe plugs. Check the turbocharger and exhaust manifold mounting. Refer to Procedure 010-058 in Section 3. |
| Engine Power Output Low | Air leak between the turbocharger and the intake manifold | Check for leaks in the air crossover tube, charge-air cooler connections, hoses, or through holes in the manifold cover and repair or replace if necessary. Refer to equipment manufacturer service information. |
| Engine Power Output Low | Charge-air cooler is restricted or leaking | Inspect the charge-air cooler for air restrictions or leaks. Refer to Procedure 010-027 in Section 4. |
| Engine Power Output Low | Fuel leak | Check the fuel lines, fuel connections, and fuel filters for leaks. Check the fuel lines to the supply tanks. Refer to equipment manufacturer service information. |
| Engine Power Output Low | Air in the fuel system | Check for air in the fuel system. Tighten or replace the fuel connections, fuel lines, fuel tank standpipe, and fuel filters as necessary. |
| Engine Power Output Low | Fuel supply is not adequate | Check the flow through the filter to locate the source of the restriction. Refer to equipment manufacturer service information. |
| Engine Power Output Low | Fuel return restriction excessive | Inspect the fuel return lines for restrictions. Refer to equipment manufacturer service information. |
| Engine Power Output Low | Fuel filter or fuel suction line is restricted | Replace the fuel filter. Check the fuel suction line for restriction. Refer to Procedure 006-015 in Section 5. |
| Engine Power Output Low | Vehicle parasitics are excessive | Check the vehicle for brakes dragging, transmission malfunction, cooling fan operation cycle time, and engine-driven units. Refer to equipment manufacturer service information. |
| Engine Power Output Low | Lubricating oil level above specification | Check the oil level. Verify the oil pan capacity. Fill the system to the specified level. Refer to Procedure 018-017 in Section V. |
| Engine Runs Rough at Idle | Engine is cold | Allow the engine to warm to operating temperature. If the engine will not reach operating temperature, refer to the Coolant Temperature Below Normal troubleshooting symptom tree in Section TS. |
| Engine Runs Rough at Idle | Electronic fault codes are active or high counts of inactive fault codes | Review instructions for reading active fault codes. |
| Engine Runs Rough at Idle | Idle speed is set too low for accessories | Check and adjust the low-idle screw. Refer to a Cummins® Authorized Repair Location. |
| Engine Runs Rough at Idle | Air in the fuel system | Check for air in the fuel system. Tighten or replace the fuel connections, fuel lines, fuel tank standpipe, and fuel filters as necessary. |
| Engine Runs Rough at Idle | Fuel filter or fuel suction line is restricted | Replace the fuel filter. Check the fuel suction line for restriction. Refer to Procedure 006-015 in Section 5. |
| Engine Runs Rough at Idle | Fuel supply is not adequate | Check the flow through the filter to locate the source of the restriction. Refer to Procedure 006-015 in Section 5. |
| Engine Runs Rough at Idle | Engine mounts are worn, damaged, or not correct | Check the engine mounts. Refer to equipment manufacturer service information. |
| Engine Runs Rough at Idle | Moisture in the wiring harness connectors | Dry the connector with Cummins® electrical contact cleaner, Part Number 3824510. Refer to equipment manufacturer service information. |
| Engine Runs Rough at Idle | Fuel grade is not correct for the application or the fuel quality is poor | Operate the engine from a tank of known high quality fuel. Refer to Procedure 018-002 in Section V. |
| Engine Runs Rough or Misfires | Engine is cold | Allow the engine to warm to operating temperature. If the engine will not reach operating temperature, refer to the Coolant Temperature Below Normal troubleshooting symptom tree in Section TS. |
| Engine Runs Rough or Misfires | Electronic fault codes are active or high counts of inactive fault codes | Review instructions for reading active fault codes. |
| Engine Runs Rough or Misfires | Air in the fuel system | Check for air in the fuel system. Tighten or replace the fuel connections, fuel lines, fuel tank standpipe, and fuel filters as necessary. Vent air from the system. Refer to equipment manufacturer service information. |
| Engine Runs Rough or Misfires | Fuel grade is not correct for the application or the fuel quality is poor | Operate the engine from a tank of known high quality fuel. Refer to Procedure 018-002 in Section V. |
| Engine Runs Rough or Misfires | Fuel leak | Check the fuel lines, fuel connections, and fuel filters for leaks. Refer to equipment manufacturer service information. |
| Engine Runs Rough or Misfires | Fuel filter is plugged | Measure the fuel pressure before and after the fuel filter. Refer to Procedure 006-015 in Section 5. |
| Engine Runs Rough or Misfires | Fuel supply is not adequate | Check the flow through the filter to locate the source of the restriction. Refer to Procedure 006-015 in Section 5. |
| Engine Runs Rough or Misfires | Engine mounts are worn, damaged, or not correct | Check the engine mounts. Refer to equipment manufacturer service information. |
| Engine Runs Rough or Misfires | Moisture in the wiring harness connectors | Dry the connector with Cummins® electrical contact cleaner, Part Number 3824510. Refer to equipment manufacturer service information. |
| Engine Shuts Off Unexpectedly or Dies During Deceleration | Engine will not restart | Refer to the Engine Difficult to Start or Will Not Start troubleshooting symptom tree in Section TS. |
| Engine Shuts Off Unexpectedly or Dies During Deceleration | Fuel level is low in the tank | Fill the supply tank. Refer to equipment manufacturer service information. |
| Engine Shuts Off Unexpectedly or Dies During Deceleration | Electronic fault codes are active or high counts of inactive fault codes | Review instructions for reading active fault codes. |
| Engine Shuts Off Unexpectedly or Dies During Deceleration | Idle Shutdown or power takeoff (PTO) Shutdown features are activated | Check the time limit on Idle Shutdown and PTO Shutdown features with an electronic service tool. Refer to Procedure 101-007 in Section 1. |
| Engine Shuts Off Unexpectedly or Dies During Deceleration | Moisture in the wiring harness connectors | Dry the connectors with electrical contact cleaner, Part Number 3824510. |
| Engine Shuts Off Unexpectedly or Dies During Deceleration | OEM engine protection system is malfunctioning | Isolate the OEM engine protection system. Follow the OEM service manual instructions to check for a malfunction. |
| Engine Shuts Off Unexpectedly or Dies During Deceleration | Battery voltage supply to the engine control module (ECM) is low, interrupted, or open | Check the battery connections, the fuses, and the unswitched battery supply circuit. Refer to equipment manufacturer service information. |
| Engine Shuts Off Unexpectedly or Dies During Deceleration | Air in the fuel system | Check for air in the fuel system. Tighten or replace the fuel connections, fuel lines, fuel tank standpipe, and fuel filters as necessary. |
| Engine Speed Surges at Low or High Idle | Fuel level is low in the tank | Fill the supply tank. Refer to equipment manufacturer service information. |
| Engine Speed Surges at Low or High Idle | Engine idle speed is set too low | Adjust the idle speed. Refer to a Cummins® Authorized Repair Location. |
| Engine Speed Surges at Low or High Idle | Electronic fault codes are active or high counts of inactive fault codes | Review instructions for reading active fault codes. |
| Engine Speed Surges at Low or High Idle | Moisture in the wiring harness connectors | Dry the connector with Cummins® electrical contact cleaner, Part Number 3824510. Refer to Procedure 101-007 in Section 1. |
| Engine Speed Surges at Low or High Idle | Air in the fuel system | Check for air in the fuel system. Tighten or replace the fuel connections, fuel lines, fuel tank standpipe, and fuel filters as necessary. |
| Engine Speed Surges at Low or High Idle | Fuel filter is plugged | Measure the fuel pressure before and after the fuel filter. Refer to Procedure 006-015 in Section 5. |
| Engine Speed Surges at Low or High Idle | Fuel supply is not adequate | Check the flow through the filter to locate the source of the restriction. Refer to Procedure 006-015 in Section 5. |
| Engine Speed Surges at Low or High Idle | Fuel grade is not correct for the application or the fuel quality is poor | Operate the engine from a tank of known high quality fuel. Refer to Procedure 018-002 in Section V. |
| Engine Speed Surges Under Load or in Operating Range | Fuel level is low in the tank | Fill the supply tank. Refer to equipment manufacturer service information. |
| Engine Speed Surges Under Load or in Operating Range | Electronic fault codes are active or high counts of inactive fault codes | Review instructions for reading active fault codes. |
| Engine Speed Surges Under Load or in Operating Range | Moisture in the wiring harness connectors | Dry the connector with Cummins® electrical contact cleaner, Part Number 3824510. Refer to equipment manufacturer service information. |
| Engine Speed Surges Under Load or in Operating Range | Air in the fuel system | Check for air in the fuel system. Tighten or replace the fuel connections, fuel lines, fuel tank standpipe, and fuel filters as necessary. |
| Engine Speed Surges Under Load or in Operating Range | Fuel filter is plugged | Measure the fuel pressure before and after the fuel filter. Refer to Procedure 006-015 in Section 5. |
| Engine Speed Surges Under Load or in Operating Range | Fuel supply is not adequate | Check the flow through the filter to locate the source of the restriction. Refer to Procedure 006-015 in Section 5. |
| Engine Speed Surges Under Load or in Operating Range | Vehicle parasitics are excessive | Check the vehicle for brakes dragging, transmission malfunction, cooling fan operation cycle time, and engine-driven units. Refer to equipment manufacturer service information. |
| Engine Speed Surges Under Load or in Operating Range | Clutch is malfunctioning or is not correct | Compare the drivetrain specifications to Cummins Inc. recommendations. Check the clutch for correct operation. Refer to equipment manufacturer service information. |
| Engine Speed Surges Under Load or in Operating Range | Fuel grade is not correct for the application or the fuel quality is poor | Operate the engine from a tank of known high quality fuel. Refer to Procedure 018-002 in Section V. |
| Engine Speed Surges in PTO or Cruise Control | Engine speed also surges at idle | Refer to the Engine Speed Surges at Low or High Idle troubleshooting symptom tree in Section TS. |
| Engine Speed Surges in PTO or Cruise Control | Engine speed surges while in the normal operating range and not in PTO or cruise control | Refer to the Engine Speed Surges Under Load or in Operating Range troubleshooting symptom tree in Section TS. |
| Engine Speed Surges in PTO or Cruise Control | Electronic fault codes are active or high counts of inactive fault codes | Review instructions for reading active fault codes. |
| Engine Speed Surges in PTO or Cruise Control | Moisture in the wiring harness connectors | Dry the connector with Cummins® electrical contact cleaner, Part Number 3824510. Refer to the Engine Speed Surges Under Load or in Operating Range troubleshooting symptom tree in Section TS. |
| Engine Speed Surges in PTO or Cruise Control | Fuel filter is plugged | Measure the fuel pressure before and after the fuel filter. Refer to Procedure 006-015 in Section 5. |
| Engine Speed Surges in PTO or Cruise Control | Fuel supply is not adequate | Check the flow through the filter to locate the source of the restriction. Refer to Procedure 006-015 in Section 5. |
| Engine Starts But Will Not Keep Running | Fuel level is low in the tank | Fill the supply tank. Refer to equipment manufacturer service information. |
| Engine Starts But Will Not Keep Running | Battery voltage supply to the control module (ECM) is low, interrupted, or open | Check the battery connections. Refer to equipment manufacturer service information. |
| Engine Starts But Will Not Keep Running | Electronic fault codes are active or high counts of inactive fault codes | Review instructions for reading active fault codes. |
| Engine Starts But Will Not Keep Running | Idle speed is set too low for accessories | Check and adjust the low-idle screw. Refer to a Cummins® Authorized Repair Location. |
| Engine Starts But Will Not Keep Running | Engine-driven units are engaged | Disengage engine-driven units. Refer to equipment manufacturer service information. |
| Engine Starts But Will Not Keep Running | Air in the fuel system | Check for air in the fuel system. Tighten or replace the fuel connections, fuel lines, fuel tank standpipe, and fuel filters as necessary. |
| Engine Starts But Will Not Keep Running | Fuel filter or fuel suction line is restricted | Replace the fuel filter. Check the fuel suction line for restriction. Refer to Procedure 006-015 in Section 5. |
| Engine Starts But Will Not Keep Running | Fuel grade is not correct for the application or the fuel quality is poor | Operate the engine from a tank of known high quality fuel. Refer to Procedure 018-002 in Section V. |
| Engine Vibration Excessive | Belt-driven accessories are malfunctioning | Check the fan hub, alternator, refrigerant compressor, and hydraulic pump for interference. Isolate belt-driven accessories and check for vibration. Refer to Procedure 008-036 in Section 6 and Procedure 013-001 in Section A. |
| Engine Vibration Excessive | Engine idle speed is set too low (electronically controlled fuel systems) | Check the engine data plate to verify the correct idle speed setting. Refer to Procedure 101-007 in Section 1. Increase the idle speed with the idle increment switch or an electronic service tool. Refer to the appropriate electronic service tool manual. |
| Engine Vibration Excessive | Engine mounts are worn, damaged, or not correct | Check the engine mounts. Refer to equipment manufacturer service information. |
| Engine Vibration Excessive | Fan is loose, damaged, or has excessive hub bearing end clearance | Check the fan. Refer to equipment manufacturer service information. |
| Engine Vibration Excessive | Engine is misfiring | Refer to the Engine Runs Rough or Misfires troubleshooting symptom tree in Section TS. |
| Engine Vibration Excessive | Electronic fault codes are active or high counts of inactive fault codes | Review instructions for reading active fault codes. |
| Engine Vibration Excessive | Crankshaft pulley is damaged or loose | Inspect the crankshaft pulley. Refer to a Cummins® Authorized Repair Location. |
| Engine Vibration Excessive | Alternator bearing worn or damaged | Replace the alternator, if damaged. See equipment manufacturer service information. |
| Engine Will Not Reach Rated Speed (RPM) | Vehicle parasitics are excessive | Check the vehicle for brakes dragging, transmission malfunction, cooling fan operation cycle time, and engine-driven units. Refer to equipment manufacturer service information. |
| Engine Will Not Reach Rated Speed (RPM) | Electronic fault codes are active or high counts of inactive fault codes | Review instructions for reading active fault codes. |
| Engine Will Not Reach Rated Speed (RPM) | Vehicle speed is too low for adequate cooling with high engine load | Reduce the engine load. Increase the engine (fan) rpm by downshifting. |
| Engine Will Not Reach Rated Speed (RPM) | Tachometer is not calibrated or is malfunctioning | Compare the tachometer reading with a handheld tachometer or an electronic service tool reading. Calibrate or replace the tachometer as necessary. Refer to equipment manufacturer service information. |
| Engine Will Not Reach Rated Speed (RPM) | Air-fuel tube leaking, wastegate diaphragm ruptured, or wastegate plumbing damaged | Tighten the fittings, repair the plumbing, and/or replace the wastegate diaphragm. Refer to equipment manufacturer service information or contact a Cummins® Authorized Repair Location. |
| Engine Will Not Reach Rated Speed (RPM) | Charge-air cooler restricted, if equipped | Inspect the charge-air cooler for internal and external restrictions. Replace the restricted cooler if necessary. See equipment manufacturer service information. |
| Engine Will Not Reach Rated Speed (RPM) | Fuel supply is not adequate | Check the flow through the filter to locate the source of the restriction. Refer to equipment manufacturer service information. |
| Engine Will Not Reach Rated Speed (RPM) | Exhaust back pressure too high | Measure and correct if above specification. Refer to equipment manufacturer service information or contact a Cummins® Authorized Repair Location. |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Documented causes: Electronic fault codes are active or high counts of inactive fault codes; Fuel grade is not correct for the application or the fuel quality is poor; Engine is operating above recommended altitude; Tachometer is not calibrated or is malfunctioning. See the table for the matching fixes.
Documented causes: Operator technique is not correct; Fuel level is low in the tank; Vehicle parasitics are excessive; Clutch is malfunctioning or is not correct. See the table for the matching fixes.
Documented causes: Starting procedure is not correct; Fuel level is low in the tank; Electronic fault codes are active or high counts of inactive fault codes; Starting aid, if necessary for cold weather, is malfunctioning. See the table for the matching fixes.