P0093 fault code: what it means

P0093: The engine computer has seen a large fuel leak in the high-pressure fuel system (mainly common-rail diesels). Fire risk if fuel is leaking outside.

Engine and gearbox (powertrain) · Safety risk

Usual causes, most likely first

leaking high-pressure fuel line, fitting or seal
leaking or stuck-open injector
worn high-pressure pump or pressure control valve
pressure relief valve stuck open

P0093 by make

BMW

Large fuel leak detected: the DME sees rail pressure dropping much faster than expected. Check for raw fuel before driving.

Usual causes: leaking high pressure fuel line or fitting; leaking injector; rail pressure sensor fault

GWM

Diesel fuel system large leak detected. Check for fuel leaks before driving.

Usual causes: leaking injector or seal; leaking high-pressure pipe; pressure relief valve

Isuzu

Fuel system large leak detected. Check for fuel leaks before driving.

Usual causes: leaking injector or injector seal; leaking high-pressure pipe; pressure limiter leaking back

LDV

Diesel fuel system large leak detected. Check for fuel leaks before driving.

Usual causes: leaking injector or seal; leaking high-pressure pipe; pressure relief valve

Mazda

SkyActiv-D: PCM has detected fuel leaking from the high-pressure system. Look for an external diesel leak before driving.

Usual causes: leaking fuel injector; fuel pipe cracked or loose; fuel pressure relief valve; supply pump or rail pressure sensor

Mitsubishi

Large fuel system leak detected: rail pressure drops faster than the injectors use fuel.

Usual causes: leaking high-pressure fuel line or fitting; injector with excessive back-leakage; fuel starvation from a blocked filter or air in the fuel

Nissan

Diesel fuel system large leak detected: rail pressure dropping faster than expected (YD25).

Usual causes: rail pressure relief valve leaking; aftermarket tuning chip asking for more fuel; suction control valve (SCV) fault; external fuel leak

Volvo

Diesel fuel system large leak detected. Look for fuel leaks before driving.

Usual causes: leaking injector or seal; leaking high-pressure pipe; pressure regulator

What the repair usually costs

CVT valve body replacement (remanufactured, in car)NZ$1,280–NZ$2,420 · A$1,200–A$2,400
A/C compressor replace incl. drier and flush (European)NZ$1,560–NZ$3,200 · A$1,490–A$3,050
Parking sensor replace, one sensorNZ$130–NZ$520 · A$130–A$510
Petrol fuel injectors (port injection, set)NZ$430–NZ$1,420 · A$400–A$1,360

Not sure what P0093 means on your car? Ask Credov.

Before you clear it

Write the code down or photograph the scanner first. A code that comes straight back after clearing points to a fault that is still there. A car whose codes were cleared just before you arrived may be hiding one: the scanner's readiness monitors show "not ready" for a while after codes are cleared.

Researched by Credov from manufacturer and workshop sources. A fault code points to where a fault may be; a workshop confirms it with a diagnosis. Browse all fault codes.