P3400 on Chevrolet: How to Diagnose & Fix
Cylinder Deactivation System Bank 1
1 Chevrolet model · 1 documented issue · 1 critical · $1,800-$4,500 repair
P3400 on Chevrolet by model: symptoms, diagnosis and fix
Automatic-transmission SS models with the 6.2L L99 V8 use Active Fuel Management lifters that are widely reported to collapse or stick, often leading to a misfire, valvetrain noise, and in many cases camshaft lobe damage. This problem is heavily documented across GM AFM-equipped V8 platforms and appears in Camaro owner complaints and forum repair threads. Repairs can become expensive because the cylinder heads and valvetrain must be opened, and many owners replace the cam and full lifter set once failure begins.
Common Symptoms
- check engine light with cylinder misfire
- ticking or tapping from valvetrain
- rough idle
- loss of power
- AFM/V4 mode drivability issues
- metal debris if cam lobe wears
How to Fix
Diagnosis usually starts with a persistent misfire, ticking, and cylinder-specific contribution loss; compression/leakdown and valvetrain inspection help confirm a failed lifter. Proper repair typically involves replacing the failed AFM lifters, trays/guides, and often the camshaft if lobe wear is present; many owners also replace related gaskets, head bolts, and oil pump components while inside. Continued driving can worsen metal contamination and increase repair cost.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Engine Valve LifterCross-ref213-1738
Fitment confirmed against the ShowMeTheParts catalog for this vehicle's year and engine.
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Sources for this issue (1)
P3400 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P3400 mean on a Chevrolet?
P3400 stands for "Cylinder Deactivation System Bank 1." This code indicates the engine control module detected a fault in the cylinder deactivation (variable displacement) system on bank 1, the side of the engine containing cylinder number one. Cylinder deactivation closes the valves and cuts fuel to certain cylinders under light load to save fuel, using oil-pressure-operated control solenoids. When the system can't operate correctly, the module sets this code; you may notice reduced fuel economy, a slight performance change, or a warning light. The most common trigger is low oil level or poor oil pressure. On Chevrolet it is documented across 1 model: Camaro.
What are the most common causes of P3400?
The most common causes of P3400 are: Low engine oil level or low oil pressure, Clogged or dirty oil passages/lifters, Faulty active fuel management / cylinder deactivation solenoid, Failed deactivating lifter or collapsed lifter, Wiring or connector fault in the solenoid circuit, Sludge from missed oil changes, Faulty oil pressure sensor. The specific cause varies by vehicle.
How much does it cost to fix P3400 on a Chevrolet?
Published repair estimates on Chevrolet range from $1,800 to $4,500 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P3400 on a different make?
View P3400 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.