Cylinder 7 Deactivation/Intake Valve Control Circuit Open
What does P3407 mean?
The P3407 code means the vehicle's onboard diagnostic system has detected: Cylinder 7 Deactivation/Intake Valve Control Circuit Open. This is a moderate severity code.
Common Symptoms
- Check Engine Light on
- Vibration during cylinder deactivation
- Rough idle
- Ticking noise from cylinder 7
- Fuel economy loss
Probable Causes (Ranked by Likelihood)
- Failed cylinder 7 deactivation solenoid Very High
- Open circuit in the solenoid wiring High
- Corroded connector Moderate
- ECM driver circuit failure Moderate
- Mechanical lifter failure on cylinder 7 Low
Step-by-Step Diagnostic Procedure
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Measure cylinder 7 deactivation solenoid resistance
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Inspect wiring and connector for opens or corrosion
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Command the solenoid with a scan tool and listen for actuation click
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Check oil pressure at the solenoid gallery
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Replace solenoid or lifter as needed
Frequently Asked Questions
Is cylinder 7 commonly deactivated on V8 engines?
Yes, on GM V8 engines with AFM, cylinder 7 is one of the four cylinders that are deactivated during light load cruising.
What is a deactivation lifter?
A deactivation lifter is a special hydraulic lifter that can collapse on command, disconnecting the valve from the camshaft lobe. This prevents the valve from opening, effectively shutting down that cylinder.
Can lifter replacement fix P3407?
If the solenoid is working but the lifter has collapsed or failed mechanically, replacing the deactivation lifter is the correct repair. This is a more involved job than solenoid replacement.