P3406: Cylinder 1 Exhaust Valve Control Performance

Where an engine controls the exhaust valves of cylinder 1 separately, P3406 would mean the exhaust side does not follow the command although the circuit checks pass. No manufacturer documents this code publicly. Ford holds a patent that detects an exhaust valve still opening after deactivation through pressure changes in the exhaust, and a GM patent, using one shared control valve, has the exhaust valves deactivate and also reactivate before the intake valves, so a lagging exhaust side is a real failure mode. Production systems from GM and Ford instead check the whole cylinder (GM P3498, Ford P3402). Electrical faults on this channel are P3405, P3407 and P3408; if the cylinder keeps pumping exhaust, the driver may feel roughness.

Medium severity. Can I keep driving?Drive little and gently. If you hear timing chain noise or the oil light comes on, shut off the engine.

Cylinder 1 is numbered according to the manufacturer: check your engine's manual before working on it.

Symptoms

Check engine lamp on
Rough running or vibration in reduced-cylinder mode
Cylinder deactivation suspended

Most likely causes

Insufficient or degraded oil delays exhaust-side switching
Exhaust lifter or rocker of cylinder 1 not latching or unlatching
Exhaust valve actuator sticking

What to check, in order

Start with the simplest. You can tick off each step.

Check the oil level and condition before anything else
Compare the reading with other engine data while varying the engine speed.
Check the solenoid valve's connector
Compare commanded and actual angles in live data
Test the solenoid valve and its filter, if it has one
Check the engine timing if there is chain noise

Good to know

Repair difficulty: hard
It affects emissions.

What each character of P3406 means

P: Powertrain: engine and transmission
3: Generic or manufacturer code, depending on the range
4: Emissions
06: Specific fault in that system

Frequently asked questions

Can I keep driving with code P3406?

Drive little and gently. If you hear timing chain noise or the oil light comes on, shut off the engine.

What causes code P3406?

The most common causes are: insufficient or degraded oil delays exhaust-side switching; exhaust lifter or rocker of cylinder 1 not latching or unlatching; exhaust valve actuator sticking.

Related codes

Sources

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.