C3960 Engine Trouble Code
What is C3960?
When C3960 code appears, first check your gas cap. Pull over safely, ensure it is tight, and inspect for cracks. A loose or damaged gas cap affects fuel-system pressure and emissions. A replacement cap costs about $3–$10. This simple fix can resolve the code and improve fuel economy.
Code Information
| Code Type: | OBD-II Chassis (C) Trouble Code |
| System: | Chassis |
| Code: | C3960 |
C3960 Symptoms
Check Engine Light
Illuminated dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration
Starting Problems
Difficulty starting the engine
C3960 Code Structure
Understanding what each digit means in the C3960 chassis trouble code:
| C | 3 | 9 | 6 | 0 |
|---|---|---|---|---|
| Chassis Code | Ignition System Or Misfire | Injector Circuit Malfunction - Cylinders | Cylinder 4 Contribution/Balance Fault | Shift Solenoid E Performance or Stuck Off |
How to Fix C3960
Diagnostic Steps:
Oxygen sensors measure exhaust gas oxygen content to optimise air-fuel ratio. This optimisation improves fuel economy and reduces emissions. Sensors degrade over time and require periodic replacement.
Repair Solution:
Disconnected, dirty, or fouled spark plugs commonly prevent proper engine operation. Replace spark plugs every season or 25 hours. Verify proper spark plug gap. If plugs are good, check ignition components: spark plug wires, coils, and ignition module.
Technical Notes:
Parts or components should not be replaced based solely on C3960 DTC. Consult your vehicle service manual for proper diagnostic procedures, possible causes, and required testing before replacement.
C3960 Description
C3960 engine trouble code is related to Shift Solenoid E Performance or Stuck Off.
Main Cause
The primary reason for C3960 OBD-II Engine Trouble Code is: Injector Circuit Malfunction - Cylinders.