P3445Cylinder Deactivation (AFM/DoD)

Cylinder 3 Deactivation/Intake Valve Control Performance

P3445 indicates a performance or stuck condition in the cylinder 3 deactivation / intake valve control system on GM AFM/DoD V8s. The lifter is not switching states as commanded.

🚗 Yes in many cases, but address before a stuck lifter causes damage.

MEDIUM

severity

🎯 Top Causes, Ranked by Likelihood

#1Stuck cylinder 3 AFM lifter$1200-$2500

40%

The classic GM AFM lifter failure on cylinder 3.

#2Low or inconsistent oil pressure$50-$400

25%

AFM needs stable oil pressure to actuate lifters.

#3Lifter oil manifold solenoid stuck$300-$700

25%

The solenoid does not flow oil correctly to cylinder 3.

#4Wrong or dirty oil$50-$150

10%

Incorrect oil affects AFM operation.

🩺 Common Symptoms

Check engine light
Lifter tick
Misfire on cylinder 3
Rough running
Reduced power

💰 Repair Cost: DIY vs Shop

DIY Cost

$100-$1500

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 P3445

1Check oil level, condition, and pressure

2Command AFM on/off with a scan tool

3Inspect the cylinder 3 solenoid and lifter

4Replace the lifter or delete AFM

❓ Frequently Asked Questions

What causes P3445?

Usually a stuck cylinder 3 AFM lifter or a solenoid that will not flow oil, often with low oil pressure.

Can I drive with P3445?

Short term yes, but a stuck lifter can damage the cam or pushrod. Fix it if you hear ticking.

Is P3445 a GM issue?

Yes, it is a common Active Fuel Management fault on GM 5.3L and 6.2L engines.

🔗 Related Codes

P3400P3441P3449P0303