Does BG 2059001 replace OE 858021002?

Yes. BG 2059001 is listed against 858021002, 11788580210, 11788580209 and A2C95505000. Confirm the number printed on the removed part and any manufacturer supersession before ordering.

Which vehicles does BG 2059001 fit?

Recorded coverage includes BMW. It is supplied as a direct-fit aftermarket def dosing modules. Adaptation, reset or relearn procedures required by the vehicle manufacturer still apply after installation.

Does this fault code always mean the def dosing modules has failed?

No. Exhaust leaks, wiring and connector damage, reductant quality, dosing performance and upstream engine faults can all produce the same codes. Validate those inputs before replacing BG 2059001.

No image available

2059001

Urea (AdBlue) Dosing Module for BMW 3 Series, 6 GT, X3 and X4 – OE 858021002

Urea (AdBlue) Dosing Module (OE 858021002) for BMW 3 Series, 6 GT, X3 and X4 SCR/AdBlue aftertreatment systems. Cross-referenced with 3 alternate OE numbers.

BG Part Number: 2059001
Category: DEF Dosing Modules
Application: BMW 3 Series, 6 GT, X3 and X4
Vehicle Manufacturer: BMW

Applications

Passenger Car

OE Cross References

858021002
11788580210
11788580209
A2C95505000

Review Inquiry Basket Ask a Technical Question

Product Description

This urea (adblue) dosing module is designed as a direct-fit replacement for BMW 3 Series, 6 GT, X3 and X4. It meters precise doses of AdBlue / Diesel Exhaust Fluid (DEF) into the exhaust stream as part of the vehicle's Selective Catalytic Reduction (SCR) aftertreatment system, converting NOx emissions into harmless nitrogen and water vapor to help the engine meet its emission standard. Primary OE reference number: 858021002. It also cross-references to OE/aftermarket numbers including 11788580210, 11788580209, A2C95505000. Manufactured by BG Brand (Wenzhou Best Growth IE Co., Ltd.) to OE-equivalent fit, form and function, this part is tested for reliable sealing and dosing accuracy, offering workshops, parts distributors and vehicle owners a quality-assured alternative to OEM pricing for scheduled SCR system maintenance and repair.

Vehicle manufacturer names, logos and OE reference numbers are used for identification and compatibility purposes only. BEST GROWTH products are independent aftermarket products and are not manufactured, sponsored or endorsed by the respective vehicle manufacturers.

BG 2059001 (OE 858021002): function on the vehicle

Urea (AdBlue) Dosing Module for BMW 3 Series, 6 GT, X3 and X4 – OE 858021002 is supplied by BEST GROWTH under part number 2059001, cross-referenced to OE 858021002, as a direct-fit aftermarket def dosing modules. In service it atomizes diesel exhaust fluid into the exhaust stream ahead of the SCR catalyst. Spray quality, dosing quantity and purge behaviour decide whether urea converts to ammonia or builds solid deposits.

BG 2059001 is built to the position defined by its OE application in passenger car service on the platform from BMW. Position, calibration and connector layout are part of the specification, so a part that physically fits is not automatically the correct part.

Seal and gasket condition at the exhaust interface is part of the repair: a leaking joint cools the spray zone and promotes crystallisation.

Fitment for BMW and OE cross reference

BG 2059001 replaces 4 OE references: 858021002, 11788580210, 11788580209 and A2C95505000. Always confirm the number printed on the removed part, including any supersession issued by the vehicle manufacturer.

Recorded vehicle coverage for 2059001 includes BMW, typically on BMW 3 Series, 6 GT, X3 and X4. Coverage lists are a starting point for identification, not a substitute for checking the OE number on the vehicle.

Where several OE numbers appear against one BG reference, they are supersessions or regional variants of the same specification. Ordering by 858021002 and quoting the number on your part lets our technical team confirm the variant before despatch.

Symptoms that lead to replacing 858021002

These complaints bring a vehicle in with the BMW def dosing modules under suspicion. None of them prove BG 2059001 has failed on its own, which is why the checks below matter before a replacement is ordered.

deposits inside the mixer restricting exhaust flow
white urea crystallisation around the dosing point or mixer
low dosing pressure or pressure-build-up fault codes
SCR low-conversion codes with confirmed in-spec DEF
coolant or DEF weeping at the module interface

Checks before fitting BG 2059001

Aftertreatment faults are usually system faults. Working through these checks prevents a repeat failure after the new def dosing modules is fitted.

Confirm the purge cycle completes at shutdown; skipped purges cause freeze damage.
Review exhaust temperature history — cold-side dosing wets the wall and forms deposits.
Check the cooling circuit or heat shield is intact before fitting a replacement.
Clean or replace the mixer if crystallisation is already established, or the new module will block too.
Verify commanded versus actual dosing pressure during an active dose, not at rest.

Quality, packaging and ordering 2059001

BG 2059001 is manufactured and tested to aftermarket replacement standards, with electrical, leakage and functional testing carried out before packing. Bulk and retail packaging, private-label cartons and customer-specific labelling are available for distributors and workshop groups.

Send OE 858021002 or the number printed on your part, the engine code and the vehicle identification number with your enquiry, and our technical team will confirm the correct reference, current stock position and lead time before you commit to an order.

Frequently asked questions

Does BG 2059001 replace OE 858021002?: Yes. BG 2059001 is listed against 858021002, 11788580210, 11788580209 and A2C95505000. Confirm the number printed on the removed part and any manufacturer supersession before ordering.
Which vehicles does BG 2059001 fit?: Recorded coverage includes BMW. It is supplied as a direct-fit aftermarket def dosing modules. Adaptation, reset or relearn procedures required by the vehicle manufacturer still apply after installation.
Does this fault code always mean the def dosing modules has failed?: No. Exhaust leaks, wiring and connector damage, reductant quality, dosing performance and upstream engine faults can all produce the same codes. Validate those inputs before replacing BG 2059001.