P2540 Low Pressure Fuel System Sensor Range/Performance — Causes & Fix

What Does P2540 Mean?

P2540 concerns the sensor watching the supply pressure feeding the high-pressure pump. A bad signal — or a genuinely starved low-pressure side — stops the ECU protecting the pump from running dry. Filters, lift pump and pipework are verified with a gauge before the sensor or wiring is replaced.

P2540 at a Glance

• What it means: The low-pressure (supply side) fuel pressure sensor signal is faulty.
• Most common cause: Blocked fuel filter or restricted supply line
• Severity: Moderate to serious — rail-pressure faults cause power loss and non-starts.
• Can you drive?: Short distances in limp mode only. Diagnose promptly.
• Typical repair cost: £40-£150 for sensor/regulator work; £100-£350 per injector where back-leak is the cause.