BMW part number 12 31 1 309 801 (12311309801) is the Generator (90A) – E30 M3/320is S14, an electrical part catalogued for the E30 (M3, 320is). As of our last check (2026-09-28, bmwfans.info), BMW lists it as no longer available new (NLA). 2 repair guides below.
Not available new according to the status source (a US dealer). NLA can be market-specific, so try the other region below.
No sourced aftermarket equivalent recorded yet. We only list brand numbers that a brand catalog or vendor page explicitly cross-references to this BMW number.
“Ships internationally” is shown only where we read it on the vendor’s own shipping page (checked 2026-09-28); otherwise check with the vendor. Import duties and taxes are the buyer’s responsibility. Amazon links carry our Associates tag, so we may earn a commission; other seller links are not affiliate links today.
No interchange recorded. That doesn't prove there isn't one; it means we have no sourced match yet.
No forum workaround recorded yet. If you know a thread, the hunt team wants to hear about it.
No kit or reman service recorded yet.
No DIY route recorded yet.
Write-ups and videos from owners, forums and specialists on removing and fitting this part. Summaries are ours; follow the link for the full steps, photos and torque values, and credit goes to the original author.
Before replacing a 'dead' Bosch alternator, check the voltage regulator: this guide shows replacing its two graphite brushes. Not applicable to the Valeo units fitted to some E30s.
Tools mentioned: Soldering iron, screwdriver
Goes beyond the usual voltage-regulator swap: how to bench-test and fully rebuild the Bosch alternator used on E30s (bearings, slip rings, diodes), using a Bosch service manual as reference.
Tools mentioned: Multimeter, bearing puller, soldering iron
Generic Bosch E30 alternator write-up; confirm your unit is Bosch.
Not listed on bmwpartsdeal (US); status from ETK data on bmwfans ('Delivery discontinued by the factory'); successor not checked – verify in ETK.
Live eBay listings are coming soon. Until then, search eBay directly for this number with the links below.