Test Groups 1BMXT03.0E5R, 1BMXT03.0E53, 1BMXV02.5M54, 1BMXV03.0LEV, 1BMXV03.0LER, 1BMXV03.0M54 & 1BMXV03.0M5R
WARNING: This page does not describe the selected car, but rather 13 other vehicles, including the 2001 BMW Z3, 2001 BMW X5, 2001 BMW M3, 2001 BMW M Roadster, and 2001 BMW M Coupe. However, it is still accessible from the selected car via links, so may be relevant.
General Description - At cold start, secondary air pump and valve are switched on for their normal operating function. Secondary air delivered into exhaust gas is causing a lean mixture indicated by output voltage of oxygen sensor. Anytime oxygen sensor indicates a lean mixture within maximum time for monitoring, a counter is incriminated by one, up to a predetermined value. This fixed limit corresponds to minimum amount of secondary air (low flow limit check). See Fig 1.