P2DED: Cylinder 4 Intake Valve Lift Range/Performance

What it means

The variable intake valve lift on cylinder 4 does not reach the commanded position within tolerance. Mechanism wear or actuator force degraded.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test
• The engine or gearbox may go into limp mode

How it works

The variable intake-lift system adjusts the opening of the intake valve on cylinder 4, with a position signal monitored by the control module. This range/performance code sets when the cylinder 4 lift mechanism does not achieve the commanded position within tolerance.

Common causes

Most likely first.

1. Variable lift mechanism worn
2. Oil pressure to actuator low
3. Sensor element aged beyond calibration window

Symptoms

• Check-engine light
• Reduced engine power or acceleration
• Rough idle or engine hesitation

How to diagnose it

1. Capture freeze-frame data and check cylinder 4 misfire counts and live lift command versus position to establish the conditions behind the fault.
2. Check engine oil level and condition, because low oil supply can limit movement of the cylinder 4 lift actuator.
3. Inspect the cylinder 4 actuator and position-sensor connectors and wiring for damage, corrosion, or poor contact.
4. Run the manufacturer's scan-tool command test for cylinder 4 lift and observe whether the position signal tracks the requested change.
5. If the circuit responds correctly, test actuator oil supply and inspect the cylinder 4 lift mechanism for binding or wear.

Common fixes

• Correct engine oil level or condition to the vehicle's specification.
• Repair damaged wiring or poor connections at the cylinder 4 lift actuator or position sensor.
• Replace the cylinder 4 position sensor if it fails the manufacturer's test.
• Repair or replace the cylinder 4 actuator or lift mechanism if inspection confirms wear or sticking.

Can I keep driving?

Limit driving and avoid hard acceleration while cylinder 4 lift operation is unreliable; the engine may hesitate or lose power. Stop if the check-engine light flashes or severe roughness occurs, because continued misfiring can damage the catalytic converter.