OBD-II code · Powertrain (manufacturer / generic)
P3403 Cylinder 1 Deactivation Stuck On
The engine control module has detected that cylinder 1 remains deactivated when activation is commanded — the deactivation hardware is stuck in the off state. Symptoms include rough running and reduced power.
Is it safe to drive with P3403?
Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.
Common causes
- Most likelyLifter stuck collapsed
- PossibleSolenoid stuck in deactivation position
- Less likelyCarbon or debris buildup preventing free movement
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 2–10 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Cylinder Deactivation Solenoid, Lifter
Related codes
- P3407Cylinder 1 Deactivation Stuck On
- P3413Cylinder 2 Deactivation Stuck On
- P3435Cylinder 4 Deactivation Stuck On
- P3400Cylinder Deactivation System Bank 1
- P3401Cylinder 1 Deactivation/Intake Valve Control Circuit Open
- P3402Cylinder 1 Deactivation Performance/Stuck Off
- P3404Cylinder 1 Deactivation Circuit Low Voltage
- P3405Cylinder 1 Deactivation Circuit High Voltage
- P3406Cylinder 1 Deactivation Stuck Off
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.