NOx Sensor A000 905 36 06

BG 201257 (OE A000 905 36 06): function on the vehicle

NOx Sensor A000 905 36 06 is supplied by BEST GROWTH under part number 201257, cross-referenced to OE A000 905 36 06, as a direct-fit aftermarket nox sensors. In service it supplies the emissions-monitoring value the OBD system uses to decide whether the SCR stage is still working within its legal window. A drifting cell triggers inducement long before the catalyst itself is worn out.

BG 201257 is built to the position defined by its OE application on a 12V electrical system in passenger car service on the platform from Mercedes-Benz. Position, calibration and connector layout are part of the specification, so a part that physically fits is not automatically the correct part.

Because the sensor carries its own control module, most "sensor" faults are really bus, supply or ground faults at the connector — the electrical side is worth ten minutes before the part is ordered.

Fitment for Mercedes-Benz and OE cross reference

BG 201257 replaces 2 OE references: A000 905 36 06 and 5WK9 6682F, covering cross applications. Always confirm the number printed on the removed part, including any supersession issued by the vehicle manufacturer.

Recorded vehicle coverage for 201257 includes Mercedes-Benz, typically on E-Class W213 / GLC 220d 2016-. 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 A000 905 36 06 and quoting the number on your part lets our technical team confirm the variant before despatch.

Symptoms that lead to replacing A000 905 36 06

These complaints bring a vehicle in with the Mercedes-Benz nox sensors under suspicion. None of them prove BG 201257 has failed on its own, which is why the checks below matter before a replacement is ordered.

• torque derate or speed inducement with a full, in-spec DEF tank
• no communication with the sensor control module after a cold start
• sensor value frozen at a fixed number once the exhaust warms up
• dosing shut-down after a few minutes of steady-state running
• upstream and downstream values reading almost identically under load

Checks before fitting BG 201257

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

• 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.
• Check for exhaust leaks ahead of the sensor boss; a diluted sample reads low NOx.
• Read the sensor's own dew-point release time — a cell that never heats is a supply or module fault.
• Verify DEF concentration with a refractometer before blaming the measuring cell.

Quality, packaging and ordering 201257

BG 201257 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 A000 905 36 06 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 201257 replace OE A000 905 36 06?

Yes. BG 201257 is listed against A000 905 36 06 and 5WK9 6682F. Confirm the number printed on the removed part and any manufacturer supersession before ordering.

Which vehicles does BG 201257 fit?

Recorded coverage includes Mercedes-Benz. 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 201257.