NOx Sensor 2872948; 4326874RX

OE Cross-Reference · Specification Check · Diagnostic Guidance

Cummins 4326873RX NOx Sensor: Cross-Reference and Replacement Guide

The Cummins 4326873RX NOx sensor is part of the SCR emissions-control feedback system used on diesel applications. Before ordering, match the OE number on the original control module and confirm the sensor voltage, cable length, connector, thread and installation position. This page covers the 12 V configuration with a 1,010 mm cable and four-pin square connector.

Important fitment note: An OE cross-reference is a starting point, not a complete fitment guarantee. The same number family can appear in catalogs covering different vehicle platforms, emissions calibrations or sensor positions. Confirm by VIN/engine serial number, original sensor label and physical specifications before installation.

Product specifications

Cummins NOx sensor OE cross-reference

Use the following numbers when comparing the original sensor label, electronic catalog and replacement part. Formatting may vary between catalogs.

Suffix reminder: “NX” and “RX” can identify service or exchange programs rather than a different electrical specification. Never assume that a suffix alone confirms voltage, position or calibration.

What the NOx sensor does in an SCR system

A NOx sensor combines an exhaust-gas probe with an electronic control module. Once the sensor reaches operating temperature, it measures nitrogen oxides in the exhaust stream and sends a processed signal to the engine or aftertreatment controller. The controller uses this feedback to monitor SCR conversion, support DEF dosing control and detect emissions-system faults.

The reading is only one part of the diagnostic picture. Exhaust leaks, incorrect DEF concentration, deposit formation, a weak dosing injector, catalyst deterioration, damaged wiring or poor power and ground can all produce symptoms that resemble a failed NOx sensor.

How to confirm the correct replacement

1. Read the original label.

   Record every OE number, manufacturer number and voltage marking before removing the sensor.

2. Confirm the application.

   Check the VIN, engine serial number, emissions family and OEM parts information.

3. Verify the electrical interface.

   Match 12 V, the four-pin square connector and the connector keying. A connector that appears similar may still be wired or keyed differently.

4. Measure the physical configuration.

   Confirm the 1,010 mm harness length, M20 × 1.5 thread and probe dimensions. The cable must follow the factory routing without tension or contact with hot and moving parts.

5. Confirm sensor position.

   Identify the sensor by its actual exhaust-system location and the OEM service information. Do not interchange inlet and outlet sensors unless the application catalog explicitly approves it.

Symptoms that require NOx sensor diagnosis

Professional diagnostic workflow

1. Save diagnostic trouble codes, occurrence counts and freeze-frame data before clearing anything.

2. Inspect the complete sensor assembly. Look for melted insulation, abrasion, corrosion, loose terminals, impact damage and an incorrectly routed harness.

3. Verify power, ground and communication according to the vehicle manufacturer's wiring diagram. Do not probe terminals in a way that spreads or damages them.

4. Warm the aftertreatment system and review live NOx, exhaust temperature and DEF dosing data under the test conditions specified by the OEM.

5. Rule out system causes such as exhaust leakage, poor DEF, crystallization, dosing faults and SCR catalyst problems.

6. Replace the sensor only when the evidence supports a sensor or integrated-module fault.

Replacement guidance

Allow the exhaust system to cool and isolate electrical power as required by the vehicle service procedure. Disconnect the electrical connector without pulling on the cable, release the harness retainers and remove the probe with the correct sensor tool. Protect the new probe from impact, grease, cleaning chemicals and fingerprints on the sensing area.

Install the replacement using the vehicle manufacturer's tightening torque and routing instructions. Do not add anti-seize compound unless the sensor supplier or OEM procedure specifically requires it; some sensors are supplied with a controlled thread coating. Secure the cable away from the exhaust surface, sharp edges and moving components, then reconnect the plug until its lock is fully engaged.

After installation, clear codes only after recording them, perform any OEM-required reset or commissioning routine, and complete a verification drive or stationary test. Confirm that the sensor communicates, reaches operating temperature and reports a plausible response without returning faults.

Why specification matching matters

NOx sensors are electronically active components, not universal oxygen sensors. Matching the thread alone is insufficient. Voltage, control-module protocol, connector keying, harness length, emissions calibration and sensor position must all agree with the application. Installing the wrong sensor can cause communication faults, inaccurate SCR feedback, warning lights or emissions inducement.

Frequently asked questions

Which numbers cross-reference with Cummins 4326873RX?

The supplied reference set includes 2872948, 2872948NX, 326873RX, 4326873, 4326873RX, 7099783C1 and 7099784C1. Confirm the complete application and physical specification before treating any cross-reference as interchangeable.

What is the voltage of this Cummins NOx sensor?

The configuration described on this product page is 12 V. Because external catalogs may group related OE numbers across more than one electrical configuration, match the voltage marking on the original part and the vehicle service data.

Can I identify an inlet or outlet NOx sensor by the OE number alone?

Not safely across every vehicle and emissions platform. Confirm the sensor's physical position, VIN or engine serial number, wiring and OEM catalog description. Inlet and outlet sensors should not be exchanged unless explicitly validated for that application.

Does a four-pin square connector guarantee fitment?

No. Pin count and connector shape are useful checks, but connector keying, voltage, communication protocol, cable length and calibration must also match.

Does a new NOx sensor require programming?

Requirements vary by vehicle and controller. Some applications need only fault clearing and a verification drive, while others specify a reset, adaptation or service routine. Follow the OEM diagnostic procedure for the exact vehicle.

Order with confidence

For an accurate quotation, provide the VIN or engine serial number, the complete number and voltage printed on the original sensor, its installation position, and clear photos of the module label, connector and probe. BG can use these details to help confirm the correct 12 V Cummins NOx sensor replacement before shipment.