BMW I01 Product Information page 47

I01￿High-voltage￿Components
3.￿Electric￿Motor
Service￿information
The￿EME￿control￿unit￿performs￿several￿self-diagnosis￿functions￿in￿order￿to￿ensure￿the￿proper￿function
of￿the￿parking￿lock￿module￿and￿to￿protect￿the￿components￿against￿damage.￿These￿self-diagnosis
functions￿are:
• Monitoring￿of￿lines￿for￿the￿electric￿motor,￿the￿position￿sensors￿and￿the￿solenoids￿for￿short
circuit￿against￿ground￿and￿supply￿voltage,￿as￿well￿as￿for￿open￿circuit
• Monitoring￿of￿the￿current￿level￿for￿the￿electric￿motor￿with￿regards￿to￿the￿maximum￿value￿and
plausibility￿for￿the￿signals￿of￿the￿position￿sensors
• Monitoring￿of￿the￿signals￿of￿the￿position￿sensors￿(pulse-width￿modulated￿signal￿in￿the
specified￿range￿and￿plausibility￿of￿both￿signals￿to￿each￿other).
If￿one￿of￿the￿self-diagnosis￿functions￿identifies￿a￿fault,￿in￿the￿EME￿control￿unit￿an￿entry￿is￿made￿in￿the
fault￿memory￿which￿can￿indicate￿the￿fault￿cause.￿Depending￿on￿the￿severity￿of￿the￿identified￿fault￿the
parking￿lock￿will￿either￿work￿again￿or￿remain￿in￿the￿current￿position.￿In￿each￿case,￿however,￿a￿fault￿code
entry￿is￿generated￿and￿the￿customer￿is￿requested￿by￿a￿Check￿Control￿message￿to￿have￿the￿vehicle
checked￿by￿BMW￿Service.
If￿the￿cause￿for￿a￿malfunction￿cannot￿be￿determined￿using￿the￿fault￿code￿entry,￿the￿Service￿employee
can￿perform￿the￿following￿checks￿and￿thus￿pinpoint￿the￿cause:
• Check￿the￿voltage￿supply￿of￿the￿electric￿motor￿at￿the￿output￿of￿the￿electrical￿machine
electronics￿with￿a￿measurement
• Check￿the￿wiring￿harness￿section￿for￿open￿circuit/short￿circuit.
The￿diagnosis￿system￿not￿only￿supports￿the￿Service￿employee￿during￿troubleshooting￿for￿the￿parking
lock.￿The￿diagnosis￿system￿also￿offers￿Service￿functions.￿The￿most￿important￿Service￿function￿is￿used
for￿the￿initialization￿of￿the￿parking￿lock.￿During￿the￿initialization￿the￿electric￿motor￿in￿the￿parking￿lock
module￿approaches￿its￿end￿positions￿several￿times.￿The￿signals￿of￿the￿position￿sensors￿and￿also￿the
characteristic￿of￿the￿current￿level,￿which￿the￿electric￿motor￿uses,￿are￿observed.￿The￿force￿which￿the
electric￿motor￿must￿apply￿and￿also￿the￿current￿characteristic￿change￿through￿the￿locking￿positions￿at
the￿cam￿disc￿and￿the￿force￿which￿the￿fixing￿element￿exerts.￿The￿EME￿control￿unit￿uses￿these￿values￿to
calculate￿the￿positions￿at￿which￿the￿parking￿lock￿is￿correctly￿engaged￿or￿disengaged.￿The￿respective
signal￿values￿of￿the￿position￿sensors￿are￿stored￿permanently￿in￿the￿EME￿control￿unit￿and￿are￿available
from￿this￿time￿for￿the￿control￿of￿the￿operation￿of￿the￿parking￿lock.
The￿initialization￿of￿the￿parking￿lock￿in￿the￿I01￿using￿the￿diagnosis￿system￿is￿necessary￿if
• the￿transmission￿was￿replaced,
• the￿parking￿lock￿module￿was￿replaced￿or
• the￿electrical￿machine￿electronics￿was￿replaced.
If￿the￿parking￿lock￿module￿is￿to￿be￿replaced,￿ensure￿that￿the￿new￿part￿is￿supplied￿in￿the￿position￿which
corresponds￿to￿the￿condition￿"Parking￿lock￿disengaged".￿Proceed￿as￿follows￿to￿install￿the￿new￿parking
lock￿module:
1 Secure￿the￿vehicle￿against￿rolling￿away￿using￿the￿parking￿brake
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