OBD-II code · Powertrain (manufacturer / generic)
P3456 Cylinder 8 Deactivation/Intake Valve Control Circuit/Open
The engine control module has detected an open or out-of-range circuit at the cylinder 8 deactivation or intake valve control solenoid. Cylinder 8 cannot be deactivated until the circuit is restored.
Is it safe to drive with P3456?
Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.
Common causes
- Most likelySolenoid coil open
- PossibleWiring or connector open
- Less likelyPin pushed back out of connector body
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–6 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Cylinder Deactivation Solenoid, Engine Wiring Harness, Ecm
Related codes
- P3417Cylinder 3 Deactivation/Intake Valve Control Circuit/Open
- P3440Cylinder 6 Deactivation/Intake Valve Control Circuit/Open
- P3448Cylinder 7 Deactivation/Intake Valve Control Circuit/Open
- P3453Cylinder 5 Exhaust Valve Control Circuit Low
- P3454Cylinder 6 Exhaust Valve Control Circuit Low
- P3455Cylinder 7 Exhaust Valve Control Circuit Low
- P3457Cylinder 7 Deactivation
- P3458Cylinder 8 Deactivation/Intake Valve Control Circuit Low
- P3459Cylinder 8 Deactivation/Intake Valve Control Circuit High
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.