instrument cluster BMW 750IL 2001 E38 Central Body Electronics ZKE Manual

The key data is stored in a transponder chip. The transponder chip is a wireless read and
write EEPROM. It is powered via the ring coil at the steering lock. Power is applied elec-
tromagnetically when the key is in the ignition switch from KL R.
The power supply is used both for data transfer as well as for charging the battery. This has
been made possible by new development of the transponder chip.
As with previous systems, every press of an FZV key also provides the battery charge con-
dition. When the FZV electronics receives a low power condition message three successive
times, the GM sets a fault indicating a low battery within a specific key. The LCM is also
informed via the bus system and alerts the driver via an instrument cluster matrix message.
If the battery is recharged (used operate car), the fault will be automatically deleted when
five successive messages are received indicating a charged battery condition.
The battery has no affect on the EWS III communication function!
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Central Body Electronics ZKE III

Battery Status
The GM monitors KL R on a dedicated circuit. If the ignition is switched on and detected
via the KL R circuit but the GM does not receive KL R status via the K Bus, the GM mon-
itors the KL R voltage level. If after an additional 0.3 seconds there is no K Bus activity, the
GM initiates an emergency running program.
A substitute value for vehicle speed is used to allow the GM to operate certain functions.
The emergency running program will terminate if the GM detects a vehicle speed or KL R
status via the K bus.
Diagnosis/Troubleshooting
The GM contains an EEPROM fault memory. Diagnosis and troubleshooting is carried out
with the DISplus or MoDiC. The diagnostic link is through the Instrument cluster over the K
bus to the GM.
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Central Body Electronics ZKE III