System: Fuel & Air Metering · Standard: SAE J2012 generic code · Severity: Repair soon
The car will usually keep running, but continued driving risks secondary damage or an emissions failure. Book the repair.
When P0171 and P0174 appear together the cause is almost always upstream of the bank split, such as the mass air flow sensor or a shared intake leak.
Start by reading every stored and pending code, not just this one. A single fault frequently sets three or four codes at once, and the first one in the freeze-frame data is usually the cause while the rest are consequences.
The controller has reached its enrichment limit on bank 2. System Too Lean (Bank 2) is a generic fuel & air metering code defined by SAE J2012, so it carries the same meaning on every OBD-II vehicle.
Repair soon. The car will usually keep running, but continued driving risks secondary damage or an emissions failure. Book the repair.
In rough order of how often they turn out to be the problem: Intake leak on bank 2; Weak fuel delivery; Faulty mass air flow sensor.
P0100 Mass Air Flow Circuit MalfunctionP0101 Mass Air Flow Circuit Range/PerformanceP0102 Mass Air Flow Circuit Low InputP0103 Mass Air Flow Circuit High InputP0106 Manifold Absolute Pressure Circuit Range/PerformanceP0110 Intake Air Temperature Circuit MalfunctionCode number, system and definition follow the SAE J2012 / ISO 15031-6 generic diagnostic trouble code standard. Symptoms, causes and severity are the standard generic diagnostic logic for that fault. This page does not contain manufacturer-specific procedures, part numbers or pricing.