P2675: Air Cleaner Inlet Control Circuit/Open
What to do
You will probably notice nothing, and nothing is at risk. This controls a flap that chooses whether the engine breathes cold outside air or air warmed near the exhaust manifold — useful for warming up quickly and for preventing throttle icing on damp near-freezing days, and useful the other way round for making full power when hot.
With the circuit open, the flap sits wherever it defaults to and the engine simply loses the choice. Expect at most slightly reduced power and marginally worse economy, or slower warming in winter.
Worth fixing rather than ignoring for two reasons: it is an emissions monitor that will not complete, which matters where emissions are tested, and on a damp winter day the warm-air setting is doing a real job. The fault is usually the connector or the actuator's wiring rather than anything expensive — this assembly sits on the airbox, where it is easy to reach and easy to knock loose during air filter changes.
What this code means
An open circuit in the control of the flap that selects where the engine draws its intake air from.
Most drivers have no idea their car chooses. An air cleaner inlet control moves a flap between two sources: cold air from outside the vehicle, and warmed air drawn from a shroud near the exhaust manifold. The module picks between them according to conditions.
Warm air exists for cold running, and for one problem in particular — throttle body icing. Air expanding and accelerating past a throttle plate cools sharply, and on a damp day near freezing that can drop the metal below the point where moisture in the air freezes onto it. Ice on a throttle plate restricts it, sticks it, and in the worst case holds it open. Drawing warmed air prevents that entirely, which is why the arrangement long outlived the carburettors it was invented for.
Cold air exists for power and for knock margin. Colder air is denser, so it carries more oxygen per unit volume, and it raises the temperature at which the mixture will detonate. An engine held on warm air when it should be on cold makes less power and retards its own ignition timing to stay out of knock.
With an open circuit the flap sits in its default position, and the practical result depends on which default the vehicle uses — so the honest summary is that the engine loses the ability to choose, rather than that it is stuck in a specific bad state.
The consequences are mild and mostly seasonal, which is why this is a low-severity code: slightly reduced power and a little more fuel used if held warm, slower warm-up and a small icing risk in specific damp near-freezing conditions if held cold. Nothing here threatens the engine.
Likely causes
Start here
- Corroded or loose connector · easy
- Open circuit in module wiring · moderate
- Faulty air cleaner inlet actuator · easy
Less common
- Seized air cleaner inlet flap · easy
- Leaking or perished vacuum hose · easy
Symptoms
Components involved
Information, not instruction
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Community experience
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