P24D6: Evaporative Emission System Pressure Sensor/Switch B Circuit Range/Performance
What to do
This will not affect how the car drives. It concerns the system that stops petrol vapour escaping from the tank, not anything to do with running.
It does matter for the MOT. While it is stored the vehicle cannot complete its evaporative emissions self-check, and an incomplete monitor can fail the test by itself — so get it looked at with time in hand rather than the week before.
Check the fuel filler cap is properly tightened, and mention if it is old or its seal looks perished. It is part of the sealed system being tested and a common contributor to related faults.
Mention any smell of fuel, which would point at a genuine leak alongside the sensor fault and raises the priority.
What this code means
The second evaporative system pressure sensor or switch is reporting a value that does not fit the conditions.
The evaporative system exists to stop fuel vapour reaching the atmosphere, holding it in a charcoal canister and drawing it into the engine to be burned. Pressure sensors are how the vehicle proves that system is sealed.
Sensor B is the second of at least two, which is what makes range/performance detectable at all: the module has another measurement to compare against. A single sensor drifting slowly is very hard to catch; two sensors that should agree and do not are conclusive.
The strongest evidence is a disagreement at rest. After the vehicle has stood, every pressure in the system should equalise to atmospheric. Two sensors that still disagree at that point have settled the question, and no running data is needed.
This code blocks the evaporative readiness monitor, so the practical consequence is an MOT problem rather than a driving one.
Check the plumbing before the sensor. These lines are thin plastic, they run under the vehicle, and a kinked, split or blocked hose isolates a sensor from the pressure it is meant to be measuring — which reads exactly like a failed sensor and costs a fraction as much to put right.
Likely causes
Start here
- Faulty fuel tank pressure sensor · moderate
- Blocked or kinked evaporative hose · easy
- Corroded or loose connector · easy
Less common
- Water ingress into connector · easy
- Faulty EVAP leak detection pump · 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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