P0170, P0173 and P0065 to P0067: fuel trim malfunction and air assisted injectors
The fuel trim on bank 1 (P0170) or bank 2 (P0173) is at fault, or the air assisted injector control has a circuit or performance fault.
SeverityModerateUsually not urgent today, but it can get worse if left.
Can you keep driving?Drive gently, check it soonWhat does P0170 mean?
Fuel trim is the correction the computer makes to keep the mixture right. Where P0171 to P0175 say whether the mixture is too lean or too rich, P0170 and P0173 are older, general codes that say only that the correction is out of bounds, so the fuel trim readings themselves show which way it goes. Air assisted injectors, used on some engines, blow a little air through each injector to break the fuel into a finer mist; if that air fails, the engine runs a little rougher and burns less cleanly.
What causes P0170?
- An air leak in the intake, if the trims are lean
- A leaking injector or high fuel pressure, if the trims are rich
- A dirty air flow meter
- A failing oxygen sensor ahead of the catalyst
- A blocked air passage or failed valve, for the air assisted injector codes
What to check first for P0170
- Read the short and long term fuel trims to see whether the mixture is lean or rich
- Inspect the intake for air leaks
- Have the fuel pressure measured, above all if the trims run rich
- Clean or test the air flow meter, above all if the trims run lean
Can you drive with P0170?
Usually you can drive to a workshop. Expect rough idle or higher fuel use, and do not leave it long, because a wrong mixture can damage the catalytic converter.
Since May 2018 an engine warning light that stays on is a major defect at the MOT, so the car fails until the fault is fixed.
Codes on this page
- P0065Air Assisted Injector Control Range/Performance
- P0066Air Assisted Injector Control Circuit or Circuit Low
- P0067Air Assisted Injector Control Circuit High
- P0170Fuel TrimBank 1
- P0173Fuel TrimBank 2
Related codes
Checked on · Rafael Soares
These are the generic meanings every manufacturer shares. Each brand adds its own detail, so your car's handbook, its service information and a qualified mechanic have the last word. OdoKeep has no connection with any manufacturer, and the app does not read codes from the car.
