P111B fault code: what it means

P111B: Air mass calculated from the oxygen sensor too low (bank 1).

Engine and gearbox (powertrain) · Minor

Usual causes, most likely first

intake leak
faulty MAF or pressure sensor
ageing oxygen sensor

P111B by make

Mini

Air mass calculated from the oxygen sensor too low (bank 1).

Usual causes: intake leak; faulty MAF or pressure sensor; ageing oxygen sensor

What the repair usually costs

CVT valve body replacement (remanufactured, in car)NZ$1,280–NZ$2,420 · A$1,200–A$2,400
Air-fuel ratio / front O2 sensor replace (upstream)NZ$270–NZ$750 · A$260–A$730
O2 sensor replace (downstream / after cat)NZ$180–NZ$480 · A$180–A$460

Not sure what P111B means on your car? Ask Credov.

Before you clear it

Write the code down or photograph the scanner first. A code that comes straight back after clearing points to a fault that is still there. A car whose codes were cleared just before you arrived may be hiding one: the scanner's readiness monitors show "not ready" for a while after codes are cleared.

Researched by Credov from manufacturer and workshop sources. A fault code points to where a fault may be; a workshop confirms it with a diagnosis. Browse all fault codes.