How does a fault code arise in the Fuel System group?
The fuel system covers the chain from the pump inside the tank to the tip of the injector: lift pump, filter, high pressure pump on direct injection engines, pressure regulator, rail pressure sensor and injectors.
Codes in this group come in two kinds that should not be confused. Circuit codes describe an electrical fault — an injector circuit open or shorted, for example. Pressure and mixture codes describe a hydraulic or chemical outcome: rail pressure is not reaching its target, or lambda feedback is constantly adding or removing fuel to correct the mixture.
For mixture codes (too lean / too rich) the first place to look is not fuel but air: a vacuum leak, a contaminated air meter or a hose leaking downstream of the measuring point all look like a fuel shortage to the module. Fuel trim values are the fastest way to make that distinction.
Fault codes in this group
The database holds 34 codes in this group. Each code has its own page with the meaning, possible causes and diagnostic steps:
Read fault codes on your own vehicle
With an ELM327-based BLE OBD2 adapter, CarCoding reads confirmed, pending and permanent fault codes separately, pulls the freeze frame and explains every code in plain language. Clearing codes is done from the app as well. The app is free to download.
Some advanced features require an in-app purchase.
Data source: the CarCoding fault code database. Code definitions follow the SAE J2012 standard; manufacturers may use different wording for their own codes. Everything on this page is generated from the code-specific database records.