Hard & Intermittent Failures

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2001 BMW Z8, 2001 BMW X5, 2001 BMW M5, 2001 BMW 750iL, and 2001 BMW 740iL. However, it is still accessible from the selected car via links, so may be relevant.

A fault code is stored within the respective control module upon first occurrence of a fault in system being checked. CHECK ENGINE light will not be illuminated until completion of second consecutive driving cycle where previously faulted system is again monitored and a fault is still present or a catalyst damaging fault has occurred. If second drive cycle was not complete and specific function was not checked, PCM counts third drive cycle as next consecutive drive cycle. CHECK ENGINE light is illuminated if function is checked and fault is still present.

If an intermittent fault is present, and it does not cause a fault to be set through multiple drive cycles, 2 complete consecutive drive cycles with fault present are required for CHECK ENGINE light to be illuminated. Once CHECK ENGINE light is illuminated it will remain on unless specific function has been checked without fault through 3 complete consecutive drive cycles.

Fault code will also be cleared from memory automatically if specific function is checked through 40 consecutive drive cycles without fault being detected or with use of DIS Plus or GT-1 scan tool. To clear a catalyst damaging fault from memory, condition under which fault occurred must be evaluated for 80 consecutive cycles without fault reoccurring.