Question 1

What does P3400 mean?

Accepted Answer

P3400 - Cylinder Deactivation System — Bank 1. The cylinder deactivation system (Active Fuel Management on GM, Multi-Displacement on Chrysler) has a fault on bank 1.

Question 2

What are the symptoms of P3400?

Accepted Answer

Check engine light, Engine misfires, Rough idle, Ticking/knocking noise, Reduced fuel economy

Question 3

What causes P3400?

Accepted Answer

Failed lifter (AFM lifter collapse), Oil control solenoid failure, Low oil pressure, Dirty oil, VLOM (valve lifter oil manifold) failure

Question 4

How much does it cost to fix P3400?

Accepted Answer

Typical repair cost: $200-$3,000. On GM V8s with AFM, collapsed lifters are extremely common. Many owners choose to delete the AFM system entirely. The VLOM (valve lifter oil manifold) gasket is a common leak point.

P3400 — Cylinder Deactivation System — Bank 1

Don't guess — diagnose P3400 the right way

Common symptoms of P3400

Common causes of P3400

Repair cost & difficulty

Vehicles commonly affected

Related trouble codes