Faulty resonance switchover valve Y226 (solenoid failed or sticking); Damaged wiring or corroded or loose connector at the valve; Cracked, split, disconnected or perished vacuum hoses to the valve or actuator; Leaking or failed vacuum actuator or reservoir for the intake flaps; Stuck or seized intake manifold flap or linkage, for example from carbon build-up or a broken lever; Fault in the engine control unit output stage.

P1476

Resonance Intake Manifold Switchover Valve Y226.

Mercedes-Benz
Powertrain
Manufacturer code
Low severity

How this code is built

P: SystemPowertrain
1: Defined byThe manufacturer
4: AreaAuxiliary emission controls
76: FaultThe specific fault in that area

What it means

On Mercedes-Benz, P1476 relates to the resonance intake manifold switchover valve (Y226), which controls flaps or a vacuum-operated mechanism that changes the intake runner length or resonance behaviour at different engine speeds. The engine control unit has detected a fault in the valve's circuit or its operation, such as an open circuit, short circuit or an implausible response. The exact fault criteria and the layout of the system vary by model and engine.

Symptoms

Engine warning light on
Loss of mid-range or top-end power
Flat spot or hesitation at certain engine speeds
Slightly higher fuel consumption
Rough or uneven running in some cases
Possible whistling or hissing from a vacuum leak

Possible causes

Faulty resonance switchover valve Y226 (solenoid failed or sticking)likely
Damaged wiring or corroded or loose connector at the valvelikely
Cracked, split, disconnected or perished vacuum hoses to the valve or actuatorlikely
Leaking or failed vacuum actuator or reservoir for the intake flapspossible
Stuck or seized intake manifold flap or linkage, for example from carbon build-up or a broken leverpossible
Fault in the engine control unit output stagerare

How to diagnose

Read all stored and pending codes and freeze frame data, then note any related codes before clearing anything
Visually inspect the valve, its connector and the wiring for damage, chafing, heat damage, corrosion or water ingress
Inspect all vacuum hoses and connections to the valve, reservoir and actuator for splits, kinks and loose fittings
Use a scan tool to activate the valve and listen or feel for it clicking, and check that the actuator moves
Check the valve's electrical supply, earth and control signal, and measure the solenoid resistance against the manufacturer's specification for that engine
Test the vacuum supply and the actuator's ability to hold vacuum with a hand vacuum pump
Check the intake flaps and linkage move freely and show no signs of carbon build-up or breakage
Check for software updates relevant to the engine control unit following the manufacturer's service information

How to fix

Replace the resonance switchover valve Y226 if it has failed electrically or mechanically
Repair or replace damaged wiring or connector terminals
Replace any cracked, perished or disconnected vacuum hoses
Replace a leaking vacuum actuator or reservoir
Clean or replace a seized intake flap mechanism, as specified for the engine
Update the engine control unit software only if the manufacturer lists it as a known fix, and replace the unit only after all other causes are ruled out

Can I keep driving?

Low severity

The car can normally be driven, as this fault mainly affects performance and economy rather than safety. Book it in soon, as a stuck or broken flap mechanism can worsen and in rare cases cause engine damage.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.