Cylinder 6 Deactivation/Intake Valve Control Circuit Open
What does P3406 mean?
The P3406 code means the vehicle's onboard diagnostic system has detected: Cylinder 6 Deactivation/Intake Valve Control Circuit Open. This is a moderate severity code.
Common Symptoms
- Check Engine Light on
- Rough running during deactivation
- Engine vibration at highway speed
- Noise from cylinder 6 area
- Reduced fuel economy
Probable Causes (Ranked by Likelihood)
- Failed cylinder 6 deactivation solenoid Very High
- Open circuit in cylinder 6 solenoid wiring High
- Corroded solenoid connector pins Moderate
- ECM driver circuit fault for cylinder 6 Moderate
- Restricted oil flow to the solenoid Low
Step-by-Step Diagnostic Procedure
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Test cylinder 6 deactivation solenoid resistance
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Inspect wiring from the ECM to the solenoid for open circuits
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Check connector for corrosion or damage
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Verify oil pressure and flow to the solenoid area
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Replace the solenoid if confirmed faulty
Frequently Asked Questions
Is cylinder 6 one of the deactivated cylinders?
On many GM V8 engines with AFM, cylinder 6 is one of the four deactivated cylinders. On other manufacturers, the deactivation pattern may differ.
Can a failed lifter cause the same code?
Yes, if the deactivation lifter for cylinder 6 has collapsed or failed mechanically, it can trigger this code even if the solenoid itself is functional.
Should I replace all solenoids at once?
It is not required, but if one solenoid fails due to age and mileage, others may be close to failure. Some mechanics recommend replacing all for long-term reliability.