Does BG 201021 replace OE 4326873?

Yes. BG 201021 is listed against 4326873 and 5WK96742A 5WK96742B. Confirm the number printed on the removed part and any manufacturer supersession before ordering.

Which vehicles does BG 201021 fit?

Recorded coverage includes Cummins. It is supplied as a direct-fit aftermarket nox sensors on 12V systems. Adaptation, reset or relearn procedures required by the vehicle manufacturer still apply after installation.

Does this fault code always mean the nox sensors 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 201021.

201021

NOx Sensor 4326873

BG NOx sensor for CUMMINS ISB / ISC / ISL Engines, OE 4326873 / 5WK96742A, 12V urea/SCR system.

BG Part Number: 201021
Category: NOx Sensors
Application: ISB / ISC / ISL Engines
Voltage: 12V
Vehicle Manufacturer: CUMMINS

OE Cross References

4326873
5WK96742A 5WK96742B· cross

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Product Description

This BG NOx (nitrogen oxide) sensor is designed for the urea/AdBlue-based SCR (Selective Catalytic Reduction) emissions system on CUMMINS ISB / ISC / ISL Engines. It is a direct-fit replacement for OE reference 4326873 / cross reference 5WK96742A; 5WK96742B. Rated for 12V electrical systems. The sensor provides accurate real-time NOx measurement for precise urea dosing control, helping maintain stable SCR performance and compliance with diesel emission standards.

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 201021 (OE 4326873): function on the vehicle

NOx Sensor 4326873 is supplied by BEST GROWTH under part number 201021, cross-referenced to OE 4326873, as a direct-fit aftermarket nox sensors. In service it acts as the closed-loop feedback element of the SCR circuit: it tells the controller how much NOx is still leaving the catalyst, so dosing is trimmed up or down instead of running to a fixed map.

BG 201021 is built to the position defined by its OE application on a 12V electrical system on the platform from Cummins. Position, calibration and connector layout are part of the specification, so a part that physically fits is not automatically the correct part.

The measuring cell is consumable. Soot loading, silicone contamination and repeated thermal shock all shorten its life, which is why a sensor can drift for months before it sets a hard code.

Fitment for Cummins and OE cross reference

BG 201021 replaces 2 OE references: 4326873 and 5WK96742A 5WK96742B, covering cross applications. Always confirm the number printed on the removed part, including any supersession issued by the vehicle manufacturer.

Recorded vehicle coverage for 201021 includes Cummins, typically on ISB / ISC / ISL Engines. 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 4326873 and quoting the number on your part lets our technical team confirm the variant before despatch.

Symptoms that lead to replacing 4326873

These complaints bring a vehicle in with the Cummins nox sensors under suspicion. None of them prove BG 201021 has failed on its own, which is why the checks below matter before a replacement is ordered.

dosing shut-down after a few minutes of steady-state running
upstream and downstream values reading almost identically under load
intermittent fault that clears after the engine cools and returns when hot
SCR efficiency below threshold or NOx-signal-implausible fault codes
DEF over-consumption with no visible leak

Checks before fitting BG 201021

Aftertreatment faults are usually system faults. Working through these checks prevents a repeat failure after the new nox sensors is fitted.

Check for a pending software or parameter update for the sensor control module on that platform.
After fitting, run the manufacturer's adaptation or relearn so stored efficiency counters reset.
Compare upstream and downstream NOx readings warmed and under load — idle values prove nothing.
Confirm supply voltage, ground quality and bus termination before condemning the sensor module.
Inspect the harness for heat damage and the connector for moisture and green corrosion.

Quality, packaging and ordering 201021

BG 201021 is manufactured and tested to aftermarket replacement standards, with electrical, leakage and functional testing carried out before packing on the 12V specification. Bulk and retail packaging, private-label cartons and customer-specific labelling are available for distributors and workshop groups.

Send OE 4326873 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 201021 replace OE 4326873?: Yes. BG 201021 is listed against 4326873 and 5WK96742A 5WK96742B. Confirm the number printed on the removed part and any manufacturer supersession before ordering.
Which vehicles does BG 201021 fit?: Recorded coverage includes Cummins. It is supplied as a direct-fit aftermarket nox sensors on 12V systems. Adaptation, reset or relearn procedures required by the vehicle manufacturer still apply after installation.
Does this fault code always mean the nox sensors 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 201021.