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 31 020 Removing and installing/replacing alternator (N57 D30 O/T 1)
Necessary preliminary tasks:
- Read out the fault memory of the DDE control unit.
- Switch off ignition.
- Disconnect BATTERY EARTH LEAD .
- REMOVE intake plenum.
- Remove DRIVE BELT FOR ALTERNATOR .
Release connector (1) and remove.
Slacken nut (2).
Tightening torque 12 52 2AZ .
Disconnect positive battery cable from alternator.
Slacken nut (1).
Remove cover from deflecting element and undo bolt (1) beneath it.
Tightening torque 12 31 2AZ .
Remove deflecting element.
Release screws (1).
Tightening torque 12 31 1AZ .
Feed out alternator upwards and remove.
NO RELATED
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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.