Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
12 42 540 Replacing safety battery terminal (SBK)
Investigate cause of triggering of safety battery terminal.
To do so, read out fault memory of airbag control unit. Note fault messages stored in memory. Rectify faults. Then clear fault memory.
Use of safety battery terminal:
- From model year 1998 in Series E38, E39, E46
- From 4/99 in E36/Z3
- in each of following new Series
The different models have different installation locations:
Battery in engine compartment
Safety battery terminal is replaced with cable up to battery positive support point.
Safety battery terminal is omitted as from 03/2002 from all E46 LHD models with 4-cylinder engines.
Battery in luggage compartment behind side trim panel
Remove side trim panel.
Follow instructions for Disconnecting and connecting battery. See 61 20 900 DISCONNECTING AND CONNECTING BATTERY NEGATIVE LEAD .
Disconnect and cover battery negative lead.
Release front side trim panel partly and fold forward.
Battery in luggage compartment under floor trim panel
Follow instructions for Disconnecting and connecting battery. See 61 20 900 DISCONNECTING AND CONNECTING BATTERY NEGATIVE LEAD .
Fold back floor trim panel (1).
Lift cover (2) on battery negative lead.
Disconnect and cover battery negative lead (3).
Release nuts (4).
Remove battery cover.
Battery in luggage compartment under spare wheel
Remove spare wheel.
Release screws.
Set air supply system (1) to one side.
Follow instructions for Disconnecting and connecting battery. See 61 20 900 DISCONNECTING AND CONNECTING BATTERY NEGATIVE LEAD .
Disconnect battery negative lead.
Disconnect supply cable (1) for vehicle electrical system.
Installation:
Remove faulty fuses and carry out troubleshooting.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.