What does it mean?
P1175 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Fuel System Malfunction (Cylinder Bank 1) . This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.
Symptoms
- Check engine light on, often with lean or rich fuel trim codes
- Rough idle, misfire-like shaking and possible stalling
- Hesitation, flat spots and reduced power under acceleration
- Hard starting, especially when the tank is low
- Noticeably worse fuel economy
- Fuel trim values on bank 1 far from zero while bank 2 stays normal
Likely causes
- Low fuel pressure or volume from a weak pump, clogged filter or restricted supply line
- Faulty fuel pressure regulator or a leaking return that drops rail pressure
- Dirty, clogged or electrically weak injectors on bank 1
- Unmetered air entering bank 1 through an intake manifold gasket, split hose or leaking injector seal
- Mass air flow sensor reading low, so the module calculates the wrong fuel quantity
- Exhaust leak upstream of the bank 1 sensor giving a false lean reading
- Contaminated fuel or excessive water in the tank
How to fix it
- Record short and long term fuel trims for both banks at idle and at higher load
- Measure fuel pressure with a gauge at idle, under snap throttle, and check that it holds after shutdown
- Test injector electrical resistance and listen with a stethoscope or use an injector balance test on bank 1
- Smoke test the intake manifold, hoses and injector seals for unmetered air
- Check the mass air flow sensor readings against expected values and clean it if contaminated
- Inspect the exhaust ahead of the bank 1 sensor for leaks
- Replace the filter, pump, regulator or injectors according to what the tests show, then clear codes and confirm trims return to normal