P3401 code meaning
Cylinder 1 Deactivation/Intake Valve Control Circuit/Open
Powertrain system Generic code P34xx codes Check engine light
What P3401 means
P3401 points to a broken control path to the solenoid that switches off cylinder 1, a cylinder that GM and Chrysler V8s and Ford's 1.5 l three-cylinder EcoBoost all deactivate. On the 2019 L84 and L86 V8s, GM looks at the low-side output while it is off: over 200 kilohm to ground counts as open, and 20 failures among 25 readings at 250 ms intervals make it a Type B fault. GM adds that some controllers store P3403 alongside. Ford's VDE monitor relies on the fault status of its smart driver and decides within 5 seconds. For the 5.7 l Hemi, a Chrysler STAR case describes a deformed manifold heat shield that rubs the MDS solenoid harness open. P3403 and P3404 cover shorts, P3402 the mechanical function. Deactivation is then locked out.
P3401 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P3401
- Check engine lamp on, on GM after the second trip
- Engine stays in all-cylinder mode
- Slightly higher fuel consumption
Common causes of P3401
- Most likelyControl wire broken or worn through, e.g. by a hot exhaust heat shield
- PossibleLoose, corroded or oil-soaked solenoid connector
- PossibleOpen coil in the cylinder 1 deactivation solenoid
- Less likelyFaulty output stage in the engine control module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Cylinder deactivation solenoidWiring harnessECM
What each part of P3401 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 3 | Mixed range: generic and manufacturer-specific codes. |
| 4 | Area: auxiliary emission controls (catalytic converter, EGR, EVAP). |
| 01 | The exact fault in that area. |
What to do next
- Note P3401 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P3401
What does P3401 mean?
P3401 means "Cylinder 1 Deactivation/Intake Valve Control Circuit/Open". P3401 points to a broken control path to the solenoid that switches off cylinder 1, a cylinder that GM and Chrysler V8s and Ford's 1.5 l three-cylinder EcoBoost all deactivate. It is a generic code, so it means the same on every make.
Is it safe to drive with P3401?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P3401 fail an emissions test?
Yes, it can. P3401 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P3401 to fix?
Difficulty: medium. A typical repair takes 0.5 to 4 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P3401 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.