P3401Cylinder Deactivation (AFM/DoD)

Cylinder 1 Deactivation/Intake Valve Control Circuit/Open

P3401 indicates an open or malfunction in the cylinder 1 deactivation or intake valve control circuit. On GM AFM/DoD engines this points to the cylinder 1 lifter oil manifold solenoid or its wiring.

🚗 Yes usually, but continued driving with a stuck lifter risks valvetrain damage.

MEDIUM

severity

🎯 Top Causes, Ranked by Likelihood

#1Cylinder 1 AFM solenoid open or failed$300-$700

40%

The lifter oil manifold solenoid for cylinder 1 is open or not responding.

#2Open or corroded wiring / connector$100-$300

30%

Break in the control circuit between the PCM and the solenoid.

#3Stuck or collapsed cylinder 1 lifter$1200-$2500

20%

A failed deactivating lifter on cylinder 1 causing mechanical faults.

#4Low oil pressure$50-$300

10%

Insufficient oil pressure prevents proper lifter actuation.

🩺 Common Symptoms

Check engine light
Lifter tick from cylinder 1 area
Misfire on cylinder 1
Rough idle
Reduced power

💰 Repair Cost: DIY vs Shop

DIY Cost

$100-$700

Shop Cost

$300-$2500

📋 Free OBD2 Code Cheat Sheet

The 50 most common codes with likely cause and DIY fix cost. Sent once, no spam.

🔧 How to Diagnose P3401

1Read freeze frame and check for cylinder 1 misfire codes

2Inspect the cylinder 1 solenoid connector and wiring

3Measure solenoid resistance and command it with a scan tool

4Replace the solenoid or lifter as diagnosis indicates

❓ Frequently Asked Questions

What does P3401 mean?

It is an open or fault in the cylinder 1 deactivation valve control circuit, typically the AFM lifter oil manifold solenoid or its wiring.

Can a bad lifter cause P3401?

Yes. A stuck or collapsed cylinder 1 AFM lifter can trigger it, often alongside a misfire and ticking noise.

Is P3401 expensive to fix?

A wiring or solenoid repair is a few hundred dollars; a lifter replacement runs $1500 or more on a GM V8.

🔗 Related Codes

P3400P3425P0301P0300