Cummins Generator Error Code 313: How to Fix It
Medium 1-2 hours Medium Severity
Verified June 2026
- Error Code
- 313
- Brand
- Cummins
- Product Type
- generator
- Severity
- Medium
- DIY Difficulty
- Medium
- Estimated Fix Time
- 1-2 hours
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Tools You'll Need
- Digital multimeter
- OBD2 or Cummins diagnostic scanner (InSite, QuickCheck)
- Socket set and wrenches (metric/SAE as per engine)
- Injector puller or deep socket
- Torque wrench
- Electrical contact cleaner
- Safety glasses and gloves
- Rags and fuel container
How to Fix Error Code 313
-
Safety First: Disconnect Power and Fuel
Fuel injectors operate at high pressure. Do not attempt to remove injectors with the engine hot or fuel system pressurized. Wear safety glasses and gloves. -
Retrieve Diagnostic Codes
-
Inspect Wiring and Connectors
Do not force connectors; use appropriate tools to release locking tabs. -
Test Injector Electrical Resistance
Refer to your engine model's service manual for exact resistance specifications. Disconnect the ECM connector before testing to avoid damage. -
Swap Injectors for Diagnosis
Be cautious of fuel spray. Have a rag ready and work in a well-ventilated area. -
Replace Faulty Injector
Ensure new injector matches part number: check engine model (e.g., QSB, QSL, B3.3). Do not overtighten as it can damage the cylinder head. -
Prime Fuel System and Test
If the engine runs rough or stalls, shut down immediately and re-check injector installation and connections.
Parts You May Need
Fuel injector (cylinder #3)
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Copper washer and O-ring kit
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Fuel injector (cylinder #3)
Check Price on Amazon
Copper washer and O-ring kit
Check Price on Amazon
Fuel injector (cylinder #3)
Check Price on Amazon
Copper washer and O-ring kit
Check Price on Amazon
Fuel injector (cylinder #3)
Check Price on Amazon
Copper washer and O-ring kit
Check Price on Amazon
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When to Call a Professional
If swapping injectors doesn't move the code, or if you are not experienced with diesel fuel systems, call a certified Cummins technician. Also seek professional help if you suspect ECM failure, as it requires specialized programming.Frequently Asked Questions
Can I continue running my generator with error code 313?
It's not recommended. The injector issue can cause poor combustion, overheating, and potential damage to the engine or catalytic converter. Shut down the generator and diagnose the problem.
What is the cost to replace a Cummins injector?
The cost varies by model, but a single injector can range from $150 to $600 for the part, plus labor ($100-300). DIY replacement saves labor but requires proper tools and knowledge.
Will error code 313 clear itself after injector replacement?
No, the code must be cleared with a diagnostic scanner. After repair, use a scanner to erase the code and verify it stays off.
How do I know which injector is cylinder #3?
Consult your engine manual. Typically, cylinders are numbered from the front (fan end) of the engine. On Cummins inline engines, #3 is the third from the front. On V-configurations, it varies. Look for markings or refer to the service manual.
Can a bad fuel injector cause other codes?
Yes. A faulty injector can trigger multiple codes such as misfire (P0303), fuel rail pressure issues, or exhaust gas temperature faults. Always clear all codes after repair and retest.