5WK96750B 5WK96750C Car Nitrogen Oxide N0x Sensor 4326864 1710806 5W-15W

The 5WK96750B is a planar dual-cell limiting current type nitrogen oxide (NOx) sensor designed for 24V medium-duty and heavy-duty diesel engine exhaust aftertreatment systems with Selective Catalytic Reduction (SCR). As an electrochemical sensor that continuously measures the concentration of nitrogen oxides and oxygen in the exhaust stream, it communicates with the engine control unit via digital CAN bus protocol, enabling precise SCR system control and regulatory compliance.

The sensor consists of a ceramic sensor element and an electronic control unit, forming a single integrated unit installed in the exhaust gas system. The sensor is used to detect the concentration of nitrogen oxides and oxygen in the exhaust gas of diesel engines, providing real-time feedback to the engine control unit to adjust air-fuel ratio and combustion parameters for increased engine operating efficiency and reduced fuel waste.

The NOx sensor is part of the nitrogen oxide reduction after-treatment system used in diesel vehicles with urea-based SCR systems. The sensor’s electrochemical sensing element (typically made of ceramic with a layer of rhodium) breaks down oxides of nitrogen into nitrogen and oxygen. The NOx controller—positioned close to the sensor—calculates the level of oxides of nitrogen present in the exhaust gas and transmits that data to the SCR controller. The SCR controller then adjusts the amount of Diesel Exhaust Fluid injected into the SCR catalyst to transform excess oxides of nitrogen into water and nitrogen.

The sensor measures the level of oxygen in the exhaust gas before and after the ceramic element, and the difference between the two measurements is used to calculate the level of NOx present in the exhaust gas. The NOx sensor transmits the NOx value in the exhaust gas to the ECU in real time after normal operation. The ECU monitors whether the NOx value in the exhaust gas exceeds the standard through a set of nitrogen oxide monitoring programs.

Important: The 5WK96750B operates on a 24V system voltage. It is designed for commercial vehicle SCR applications including trucks, buses, and industrial equipment. Do not install on 12V passenger car electrical systems unless explicitly verified for dual-voltage compatibility.

The following part numbers are directly interchangeable with 5WK96750B. When searching for a replacement, these numbers may appear on the original sensor label, in supplier catalogs, or in vehicle manufacturer documentation. Always verify physical connector type, cable length, and voltage rating before purchasing.

From multiple supplier sources, the following cross-references have been verified:

• 5WK96750C is listed with cross-references including 4326864, A045S158, A2C11879500, 2P0906261B, 22028, 4326472, and 1710806.

• 4326864 is cross-referenced with A2C95992900 and confirmed as a 24V sensor.

• 4326472 is listed as an available 24V model for Cummins alongside other NOx sensors.

• 2872943 has been identified as a compatible OE number for this sensor family.

A comprehensive NOx sensor cross-reference list for this family includes: 4326864, 5WK96750C, A045S158, 5WK96750A, 4326472, 5WK96750B, and 2872943.

⚠️ Suffix and supersession caution: Different suffixes (A vs. B vs. C) may indicate minor production revisions or calibration differences. While these variants are generally interchangeable within the same series, different suffixes may have distinct CAN message IDs or heater calibration parameters. Match the full alphanumeric string on your original sensor whenever possible. Do not rely solely on partial number matches. The suffix C variant (5WK96750C) is widely listed for Cummins ISM and other compatible engine platforms.

The 5WK96750B NOx sensor is designed for 24V commercial vehicle electrical systems and is widely used across medium-duty and heavy-duty diesel engine platforms. Application coverage spans Euro V / Euro VI compliant commercial vehicles and off-highway equipment.

This sensor is most closely associated with Cummins diesel engines in commercial vehicle applications. The 5WK96750C variant (same series) is specifically identified as precision-engineered for Cummins ISM, Porte, and other compatible engines.

Based on cross-reference information and supplier listings, the 5WK96750B and its series variants are compatible with the following engine platforms:

The 5WK96750B is found in a wide range of 24V commercial vehicle applications:

• Heavy-duty trucks – long-haul and regional transport (Euro V / Euro VI)

• Medium-duty trucks – delivery and utility vehicles

• Buses and coaches – public transportation with SCR aftertreatment

• Construction equipment – diesel-powered machinery with emission controls

• Industrial equipment – SCR-equipped diesel-powered industrial machinery

• Marine auxiliary engines – genset applications with emission controls

• Generator sets – stationary diesel power generation with SCR systems

The 5WK96750B is designed for vehicles meeting:

• Euro V and Euro VI emission standards

• EPA 2010 and later (North America)

• China 5 and China 6 (Asian markets)

• Equivalent Tier standards for off-road equipment

The sensor operates on a 24V power supply and includes ECU programming compatibility. This makes it suitable for most heavy-duty diesel platforms manufactured after the introduction of SCR-based emissions compliance systems.

Due to the diversity of commercial vehicle configurations, physical fitment alone does not guarantee proper function. To confirm compatibility:

1. Check your original sensor label – Match the full part number including suffix (A, B, C, etc.)

2. Verify voltage – The 5WK96750B is a 24V sensor; confirm your vehicle electrical system is 24V

3. Count connector pins – Square 4-pin sealed connector type

4. Measure cable length – Approximately 600 – 650 mm

5. Check ECU compatibility – Some platforms require software adaptation after sensor replacement

6. Confirm thread size – M20 x 1.5 external thread (verify against your original)

⚠️ Important note: Compatibility extends beyond physical fitment. The sensor must match the ECU’s CAN communication protocol. Different vehicle manufacturers may use different calibration parameters even when the physical sensor appears identical. Always reference your original sensor part number or consult vehicle-specific documentation before purchasing. Common online resources recommend checking the original OE number before making payments to ensure correct product fitment for your vehicle.

A degraded or failed 5WK96750B NOx sensor will typically trigger one or more of the following symptoms. Early recognition can prevent secondary damage to the SCR catalyst, DEF injector, Diesel Exhaust Fluid system, or Diesel Particulate Filter. The ECU monitors the NOx sensor data and reacts when readings become inconsistent or implausible.

The most common first indicator is the activation of the check engine light on your dashboard. The ECU detects inconsistent or missing NOx data and triggers a fault code to alert you of an emissions-related issue. A faulty NOx sensor often illuminates the vehicle‘s check engine light. Common symptoms also include SCR or NOx-related fault codes.

When NOx readings become inconsistent or implausible, the ECU reacts to protect emissions systems by limiting torque and engine speed. Commercial vehicles may experience speed limitation (typically 5-20 mph or restricted RPM) until the issue is resolved. This is commonly referred to as “limp mode” and is a protective measure to prevent emissions compliance violations.

A faulty NOx sensor disrupts the ECU and SCR, triggering fault codes and leading to incorrect DEF dosing. False high NOx readings cause the SCR to over-dose DEF, resulting in rapid AdBlue depletion and potential crystallized injector. This is one of the most costly indirect symptoms.

A malfunctioning NOx sensor can cause the engine control unit to adjust the air-fuel ratio to reduce emissions, which can lead to decreased fuel efficiency. Fuel consumption can increase by 15-25% as the engine operates in a suboptimal state. A faulty NOx sensor can also cause the engine to operate less efficiently, leading to decreased fuel mileage.

A malfunctioning NOx sensor can cause your engine to idle roughly or inconsistently. A failing NOx sensor can also result in erratic or unstable idling as the ECU compensates for inappropriate readings.

You may encounter weak acceleration, low engine power output, and poor gas mileage. Uneven or erratic acceleration is a common sign of a faulty NOx sensor as the engine control unit compensates for the inappropriate reading by using more fuel.

One characteristic symptom of a failing NOx sensor is repeated warnings that return after being cleared with a diagnostic tool. If a DTC related to the SCR or NOx sensor returns shortly after being cleared, it strongly indicates a persistent sensor or system fault.

Overdosing of DEF leads to ammonia slip (NH₃), which may be visible as white vapor with a sharp, pungent odor exiting the tailpipe. This indicates excess DEF is being injected into the SCR catalyst and not being fully consumed.

If the internal heater fails (open circuit), the sensor never reaches operating temperature, and DTCs set immediately after cold start. DTC codes such as P2202 or P2203 may appear, indicating NOx sensor circuit low or high input.

Common codes associated with NOx sensor failure include:

If your vehicle is showing any of these error codes (P229F62, P229F, P229E, P2200, P2201, P2202, U029E00, U029E), it typically means the NOx sensor has failed.

Before replacing the 5WK96750B, perform these basic checks:

1. Visual inspection – Look for damaged cable insulation, chafing against chassis components, bent pins, or a melted/cracked connector. Common causes of failure include dust buildup on the sensors, water ingress to the ECU, and/or damaged cables.

2. Heater resistance test – Measure between heater positive and heater ground pins using a multimeter. Typical resistance at 20°C is between 3-15 Ω. An open circuit or short indicates internal failure.

3. Voltage supply – With key on and engine off, verify 24V power at the sensor connector.

4. CAN bus integrity – Check CAN High and CAN Low lines for proper termination and absence of short circuits to ground or battery.

5. Live data review – Using a diagnostic scan tool, observe NOx readings with key on, engine off. It should read ambient air values (0-30 ppm). A fixed reading of 0 ppm or pegged at maximum without change points strongly suggests a faulty sensor.

Note: A recurring NOx sensor code may also be caused by an exhaust leak upstream of the sensor, poor DEF quality, a failed DEF injector, a contaminated SCR catalyst, or J1939 communication issues on the vehicle’s CAN network. Perform a thorough system diagnosis before sensor replacement to avoid repeat failures.

Purchasing the correct 5WK96750B NOx sensor and installing it properly is essential for reliable SCR performance and avoiding costly mistakes. Commercial vehicle operators should pay special attention to electrical and communication compatibility.

• Match the full printed number on your original sensor, including the suffix (A, B, C, etc.). Different suffixes may have different CAN message IDs or heater calibration parameters.

• Check supersession information – The suffix C variant (5WK96750C) may be a later production revision with the same physical characteristics but potentially different calibration.

• Avoid “universal fit” listings – The 5WK96750B is a specific digital device; generic sensors claiming to fit “all 24V diesels” are unlikely to communicate correctly with your ECU.

• Always check the original OE number before making payments to ensure correct product fitment.

• Reputable supplier – Choose a supplier with documented quality control (IATF 16949 or ISO 9001 certification) and a minimum 12-month warranty.

• Avoid used or “remanufactured” – NOx sensors degrade internally from heat and contamination. Used sensors almost always fail prematurely.

• Price guideline – Authentic quality replacements typically range from $65 to $150 for standard aftermarket options. Suspiciously low prices may indicate counterfeit or defective products.

• Packaging – New sensors should be shipped in anti-static, moisture-proof packaging with a protective cap over the ceramic tip.

• Certification – Look for suppliers with TS16949 and CE certification, indicating quality management system compliance.

• Do not touch the ceramic sensing tip – Skin oils cause thermal shock cracking during the first heat-up cycle.

• Inspect cable routing – Ensure the new cable follows the original path, using existing clips and standoffs. Avoid sharp bends or contact with moving parts.

• Clean the bung threads – Use a thread chaser (M20 x 1.5) to remove carbon buildup and rust before installation. Thoroughly clean the bung threads before installing the new sensor.

• Remove protective cap only when ready – Keep the sensor clean by removing the protective cap immediately before installation.

• Do not wipe lubricated threads – If anti-wear agent is present on the threads from the manufacturer, do not wipe it clean.

Follow this sequence for proper installation:

1. Secure the ECU unit – Use screws to mount the sensor’s electronic control unit to the vehicle. Follow torque specifications (maximum permissible torque less than 60 N/mm²).

2. Remove protective cap – Immediately before installation, remove the protective cover from the sensor probe. Do not allow dirt to contaminate the lubricated threads.

3. Install the probe – Insert the sensor probe into the exhaust pipe bung. Hand-tighten the hexagon nut while holding the sensor body to prevent cable twisting.

4. Torque properly – Use a torque wrench for final installation to meet manufacturer specifications. Recommended torque for M20 x 1.5 threads: 40–60 Nm (50 ± 10 Nm).

5. Connect the harness – Connect the mating 4-pin connector to the sensor. Ensure the connector interior is clean and dry.

6. Secure the cable – Use original routing clips and standoffs to secure the harness away from heat sources and moving parts.

A new NOx sensor will not function correctly until the ECU learns its baseline values and performs a plausibility check. Many returns are caused by skipped adaptation, not a defective part. Follow these steps:

1. Install the sensor and securely connect the wiring harness

2. Clear all existing DTCs using a professional scan tool capable of commercial vehicle diagnostics (e.g., J1939 compatible tool)

3. Perform “NOx sensor replacement adaptation” – This function is typically found under “Special functions,” “SCR system,” or “Aftertreatment service” in diagnostic software. The ECU may command a specific warm-up sequence

4. Reset SCR learned values (if available) – This clears previously stored efficiency values from the old, potentially faulty sensor

5. Perform a forced SCR system test – If your diagnostic tool supports it, run a forced SCR efficiency test

6. Drive cycle – Complete a 15-20 minute mixed driving cycle at operating temperature with varying engine loads

7. Verify readiness – After the drive cycle, check for any returning DTCs. Monitor live NOx data: it should fluctuate logically (higher readings under heavy load, lower readings at idle)

Without proper adaptation, you may still see DTCs (e.g., P2200, P229E) even with a brand new sensor. Always perform the adaptation procedure after replacement.

• Wiring harness condition: Commercial vehicles operate in harsh environments (vibration, heat, moisture, road salt). Inspect the full harness length for chafing, corrosion at connectors, and damaged insulation before condemning the sensor.

• SCR system health: A recurring NOx sensor code may indicate a failed SCR catalyst, DEF quality issues, or a clogged DEF injector. These should be diagnosed before replacing the sensor a second time.

• Multiple sensor positions: Some platforms use two NOx sensors (upstream and downstream of the SCR catalyst). Verify which position requires replacement.

• ECU software updates: In some cases, a recurring NOx sensor issue may be addressed by an ECU software update rather than repeated sensor replacement.

• J1939 network issues: NOx sensors communicate via the J1939 CAN network. If the vehicle has other communication-related faults, address those first.

• In regions with mandatory emissions testing (EU, California, China, Australia, Brazil), a non-functioning NOx sensor will cause the MIL to illuminate, resulting in automatic inspection failure.

• It is illegal to defeat, delete, or simulate the NOx sensor signal in any on-road vehicle. Always replace with a fully functional sensor.

• Commercial fleets subject to emissions auditing must maintain properly functioning SCR systems, including accurate NOx sensing.

• Before purchasing, confirm the supplier offers a return or exchange for compatibility errors, preferably within 30 days of receipt.

• Keep your original sensor until the new one is confirmed working – it serves as the ultimate reference for part number and fitment.

• Request a data sheet or installation guide that includes pinout and adaptation steps if available.

• Most reputable suppliers offer a 12-month warranty against manufacturing defects.

The NOx Sensor 5WK96750B is a critical emissions aftertreatment component for 24V medium-duty and heavy-duty diesel commercial vehicles. It provides real-time NOx and O₂ measurement to the ECU for precise SCR control, enabling compliance with Euro V / Euro VI emission standards.

Designed for Cummins engine applications (including ISM, N Series, and compatible diesel platforms), this sensor is widely used in commercial vehicle platforms including Dongfeng trucks and buses. The sensor features a square 4-pin sealed connector, approximately 600-650 mm cable length, and M20 x 1.5 external threads.

Cross-references for this sensor include 4326864, 2872943, 4326472, A045S158, 5WK96750, 5WK96750A, and 5WK96750C.

Proper selection (matching part number and cross-references), confirmation of 24V system voltage, careful installation using correct torque (40-60 Nm), and mandatory ECU adaptation ensure full emissions compliance, optimal fuel economy, and reliable SCR system performance. Use this guide to confidently purchase and replace a failed 5WK96750B NOx sensor without compatibility issues or repeat failures.

For further technical support, refer to your engine or vehicle manufacturer’s service documentation or consult a qualified diesel emissions specialist.