P00C6: Fuel Rail Pressure Too Low - Engine Cranking Bank 1
What to do
Say whether the car starts fine when restarted straight away but badly after standing for hours. That is the most useful thing you can report — it means pressure is leaking away while parked, which points at an injector or a valve rather than the pump.
Also say whether hot starts are worse than cold ones, since that distinguishes several causes.
Ask when the fuel filter was last changed. A restricted filter starves the high pressure pump and is the cheapest cause.
Do not ignore it because the car runs fine once started. This is an early warning from the hardest moment for the fuel system, and it generally develops into a car that will not start at all.
What this code means
The fuel rail did not reach the pressure needed to start while the engine was cranking.
Cranking is the hardest moment for a high pressure fuel system, and this code names exactly that moment rather than running operation. The high pressure pump is driven by the engine, so at cranking speed it turns a fraction as fast as it does at idle — it has the least capability precisely when the rail must be filled from nothing.
That makes this a genuinely sensitive early warning. A system that is marginal shows here first and runs perfectly once started, so a car that takes several seconds to fire and then behaves normally is the classic presentation.
The causes divide by whether pressure is being lost or never built.
- Pressure bleeding away while parked. A leaking injector, a passing pressure control valve, or a failed non-return valve means the rail starts every crank from empty. The tell is that it starts fine if restarted immediately but poorly after standing.
- Insufficient supply. A restricted filter or weak lift pump starves the high pressure pump.
- A worn high pressure pump, which can still meet running demand but not cranking demand.
- Air in the system, which is compressible and prevents pressure building at all.
Ask whether hot restarts are better or worse than cold ones. That single question separates the first cause from the rest.
Likely causes
Start here
- Restricted fuel filter · easy
- Leaking fuel injector · specialist
Less common
- Worn injection pump metering assembly · specialist
- Air drawn into the fuel supply · moderate
- Stuck fuel pressure regulator · 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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