P2394: Diesel Intake Air Flow B Control Stuck Open
What to do
Drives normally, shudders at switch-off, keeps EGR codes as company — that trio is this fault. Cleaning before replacement.
What this code means
The second intake air flow valve is stuck open — mechanically, with its circuit answering fine.
Stuck open is the benign direction, because open is the running position: the engine breathes normally and drives normally. What is lost is what the valve existed to add — the pressure drop that drives EGR on its path (so EGR-insufficient codes are this fault's usual company) and the smooth shutdown (so the switch-off shudder returns). Carbon is the family's sculptor as ever, and the cleaning-first economics of P2391 apply.
Likely causes
Start here
- Carbon-coated EGR throttle valve · moderate
- Failed EGR throttle actuator · moderate
Less common
- Broken manifold runner linkage · moderate
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
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