2003 BMW Z4 Battery

  • 1 POST
  • 2003 BMW Z4

Electrical problem
2003 BMW Z4 4 cyl Two Wheel Drive Automatic 76000 miles

I need to replace the original battery in my 2003 Z4. Is there any special precauton I need to take before disconnecting the old battery? I'm concerned about losing any stored information or damaging computer software during the time when there is no battery connected.

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Tuesday, July 6th, 2010 AT 3:25 PM

2 Replies

  • 77,150 POSTS

Hi kycoalminer,Welcome to 2carpros and TY for the donation.

Instructions For Disconnecting And Connecting Battery

Observe safety instructions for handling vehicle battery.

Before disconnecting battery:
Switch off ignition.

NOTE: If the ignition is not turned off when the battery is disconnected, fault memories may be set in some control units.

**Danger of mixing up: If the battery positive and negative leads are the same color and you are in doubt, follow the polarity to the battery, then mark and cover the leads.
**On vehicles with radio code: After disconnecting the battery, the radio code must be re-entered. Therefore obtain the radio code card from the customer beforehand. Note down programmed stations and store these stations back in memory once the battery has been reconnected.
**Stored settings of the on-board computer and clock will also be lost.
**All available keys must be recoded for cars with first generation infrared transmitter locking systems.

General notes on disconnecting battery:
**The battery and the leads to the alternator and starter motor must not be disconnected while the engine is running.
**Detach terminal of battery negative lead from car battery and second battery if fitted. Cover battery negative terminal(s).
**When work is carried out on the electrical system, faults may be caused in the fault memories of some control units when the battery is connected.

After connecting battery:

CAUTION: Required in various models:

*E36 only: Initialize power window
*Initialize sunroof


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Tuesday, July 6th, 2010 AT 7:06 PM
  • 9,733 POSTS

Your donation is very generous, thank you. The Z4 has no issues with the replacement of the battery, just remember to be cautious when handling the old one, it may have some electrolyte on the outside, and it can cause burns. Remove the negative terminal first, clean the posts and terminals, and use the correct replacement battery. Loss of data will not occur as it is a non-volatile type memory. Damage should not be any issue, replace your battery and enjoy your Z4

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Tuesday, July 6th, 2010 AT 7:13 PM

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