P045E: Exhaust Gas Recirculation B Control Stuck Open
What to do
Say whether the engine idles roughly or stalls when you come to a stop but feels fine at speed. That pattern fits this fault exactly and is the most useful thing you can report.
Ask whether the valve can be cleaned rather than replaced. Carbon build-up is the usual cause, these valves are expensive, and one that frees up and holds position afterwards has been genuinely repaired.
Mention any black smoke, particularly when pulling away.
A pattern of short journeys makes this much worse. Regular longer runs at sustained speed keep the recirculation system considerably cleaner, and are worth building into how the car is used once it is fixed.
What this code means
The second EGR valve is stuck open, recirculating exhaust gas when it should not be.
A second EGR valve usually means the engine has two recirculation paths, and knowing which is which shapes the diagnosis. High-pressure EGR takes gas from before the turbine and feeds it after the compressor — fast-acting, hot, and used at low load. Low-pressure EGR takes gas from after the particulate filter and feeds it before the compressor — cooler, cleaner, and used at higher load.
Valve B is commonly the low-pressure one, though it can be a second bank's valve on a V engine, so confirm before diagnosing.
Stuck open is the direction that causes real driveability complaints. At idle and on light throttle the engine should be getting little or no recirculated gas — it needs clean air to burn stably. A valve stuck open dilutes the charge at exactly the wrong moment, which produces a rough, hunting idle, hesitation when pulling away, black smoke, and in the worst case a stall at junctions.
A driver reporting 'it idles badly and stalls when I come to a stop, but it is fine on the motorway' is describing this precisely.
Carbon is the cause in the overwhelming majority of cases. A low-pressure valve sits in a cooler, wetter gas stream, so its deposits are more like a sticky sludge than dry soot — which is why it binds rather than jams solid, and why cleaning often genuinely works.
Likely causes
Start here
- Carbon build-up in the EGR system · moderate
- Stuck or seized EGR valve · moderate
Less common
- Restricted EGR passage · moderate
- Broken valve return spring · moderate
- Open or shorted solenoid winding · moderate
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
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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