Cylinder 4 Deactivation/Exhaust Valve Control Circuit Open
What does P3412 mean?
The P3412 code means the vehicle's onboard diagnostic system has detected: Cylinder 4 Deactivation/Exhaust Valve Control Circuit Open. This is a moderate severity code.
Common Symptoms
- Check Engine Light on
- Rough running during cylinder deactivation
- Engine vibration
- Tapping noise from cylinder 4 exhaust area
- Reduced fuel economy
Probable Causes (Ranked by Likelihood)
- Failed cylinder 4 exhaust deactivation solenoid Very High
- Open circuit in cylinder 4 exhaust solenoid wiring High
- Corroded connector pins Moderate
- ECM driver circuit fault Moderate
- Collapsed exhaust deactivation lifter Low
Step-by-Step Diagnostic Procedure
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Measure cylinder 4 exhaust deactivation solenoid resistance
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Inspect wiring for open circuits or damage
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Check connector for corrosion
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Command solenoid on/off with scan tool
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Inspect exhaust lifter if solenoid tests good
Frequently Asked Questions
Does P3412 affect the intake valve too?
No, P3412 is specific to the exhaust valve deactivation circuit on cylinder 4. The intake valve solenoid has its own separate code (P3404).
Can both intake and exhaust solenoids fail on the same cylinder?
Yes, it is possible for both solenoids to fail independently. If both codes appear for the same cylinder, the lifter or oil supply may be the root cause.
What oil specification should I use?
Use the exact oil specification listed in your owner's manual. For GM trucks with AFM, Dexos1-approved oil is required. Using the wrong oil can contribute to deactivation system failures.