P0171 is a diagnostic trouble code that means the engine’s air-to-fuel mixture on Bank 1 is too lean, with too much air relative to the amount of fuel being delivered. The most common cause is a ...

Onboard diagnostics (OBD) systems have been around since the 1980s and were developed to help limit harmful automotive exhaust emissions. Between 1988 and 1995, U.S.-built vehicles came with what's ...