Car Parts Guide
STARTER MOTOR BMW 3 Series (2019– G20) · PARTS GUIDE

BMW 3 Series Starter Motor: Specs, Fitment & Common Faults

How to tell a failing starter motor from a flat battery, and what actually fits your specific engine.

Generation covered: this guide is for the seventh-generation 3 Series (G20 platform, 2019–present), with particular focus on 2019–2023 registered examples now old enough for parts to be a common search. The previous F30 generation (2012–2019) uses different part numbers throughout — check your logbook or VIN if you're unsure which generation you have.
Illustration of a starter motor Illustration for editorial purposes
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Often Confused With a Battery Problem

A BMW 3 Series that won't start gets blamed on the battery first, more often than not correctly — but a healthy battery paired with a failing starter motor produces some genuinely similar symptoms, which leads plenty of people to replace the wrong part first.

BMW 3 Series Starter Motor reference plate
Before you buy: starter motor specification varies by engine size and, on some versions, whether the car has stop-start technology. Always confirm against your VIN before ordering.

OEM Part Number: 12417645979

Accuracy note: confirmed below across multiple genuine BMW parts retailers, split by petrol vs hybrid powertrain. Starter motor specification differs between the four-cylinder B46/B48 and six-cylinder B58 engines given their different cranking demands — confirm your exact engine before ordering, and note that a weak battery is a far more common cause of slow or failed starting on this car than a genuine starter motor fault.
330i / 430i (B48 petrol)BMW OEM: 12417645979
Later G20/G28 range (petrol, broader fitment)BMW OEM: 12419847303
330e hybrid (B46X/B48X/B58X)BMW OEM: 12418687064

BMW 3 Series Starter Motor: What It Does

On the BMW 3 Series, the starter motor uses electrical power from the battery to physically turn the engine over, initiating the combustion cycle. On cars with stop-start systems, this component works considerably harder than on older designs, since the engine restarts far more frequently — which is why stop-start cars often use a reinforced starter motor rather than a standard unit.

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BMW 3 Series Starter Motor: Symptoms, DIY Difficulty & Aftermarket Advice

These are the same regardless of make or model — see our full Starter Motor Guide for symptoms to watch for, confirming fitment against your VIN, and aftermarket advice.