Cylinder Deactivation System Disabled
What does P3418 mean?
The P3418 code means the vehicle's onboard diagnostic system has detected: Cylinder Deactivation System Disabled. This is a low severity code.
Common Symptoms
- Check Engine Light on
- Cylinder deactivation no longer engages
- Slightly higher fuel consumption
- No vibration or rough running
- Other deactivation-related codes may be present
Probable Causes (Ranked by Likelihood)
- Previous deactivation system fault causing ECM to disable the system Very High
- Aftermarket tuner or device disabling the system High
- ECM software issue or calibration error Moderate
- Multiple solenoid failures causing system shutdown Moderate
- Low oil pressure detected by the ECM Low
Step-by-Step Diagnostic Procedure
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Scan for all stored codes -- other deactivation codes will reveal why the system was disabled
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Check if an aftermarket tuner or AFM disabler is installed
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Verify engine oil level and pressure
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Address any underlying deactivation fault codes first
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Clear codes and test drive to see if the system re-enables after repairs
Frequently Asked Questions
Why was the deactivation system disabled?
The ECM disables the deactivation system when it detects a fault that could cause drivability issues or engine damage. This is a protective measure until the underlying problem is repaired.
Is it bad to drive with deactivation disabled?
No, the engine runs perfectly fine on all cylinders. You will simply not get the fuel economy benefit of cylinder deactivation during light load driving.
Will P3418 clear on its own after repairs?
Once the underlying fault codes are repaired and cleared, P3418 should also clear, and the deactivation system should re-enable during normal driving.