Pair of Nitrogen Oxide (NOx) Sensors for Vauxhall/Opel Astra K 1.6 CDTi | OEM 55495596 & 55495597

The Pair of NOx (Nitrogen Oxide) Sensors – OEM 55495596 & 55495597 are emissions-control sensors designed for the Vauxhall/Opel Astra K 1.6 CDTi diesel engine. These sensors monitor the level of nitrogen oxides (NOx) in the exhaust gases at different points in the exhaust system, providing crucial data to the engine control unit (ECU) to optimise combustion, reduce harmful emissions and ensure the vehicle meets environmental regulations. A faulty NOx sensor can trigger warning lights, reduce engine performance and fail emissions tests, so replacing worn or damaged sensors with this paired set helps restore emission control efficiency and driving reliability.

OEM Number: BNX74072, DN10101812, 935511, 55500321, A1065596, 55495597, 899239, V40720050, 0899346, V40720072, LSN044

Product details:

Placement on Vehicle : Bank 2, Rear, Post Cat, After Catalytic Converter, Position 2

Cable Length : Approx. 945 mm

Number of Pins : 6 Pin Connector

Connector Shape : Oval

Number of Mounting Bores : 2

Thread Size : M18 x 1.5

Spanner Size : 22

Quantity: 2

Sur SKU: TVAU55495596-97PAIR_94


All our Pair Nox Sensor are OEM quality and reliable after market car parts. This Pair Nox Sensor is specifically compatible with Opel: Astra, Vauxhall: Astra, .

Please use our make-model-year tool to check this part's compatibility with your vehicle. However, please note that our tool is for reference only and we recommend that you check the part number on your old unit prior to purchasing.

If you are still not sure about the compatibility of this part to your vehicle, please supply us with the VIN number or Reg number in our live chat or contact form! You can also find details on our purchasing & shipping guide here.

Key Benefits

• Complete Pair (Position 1 & Position 2): Supplied as a matched set covering both pre- and post-catalytic converter locations (or front/rear NOx sensor positions), ensuring full emission monitoring where required by the ECU.

• OEM-Referenced Quality: Matches original part numbers 55495596 (first sensor) and 55495597 (second sensor) specified by Opel/Vauxhall for diesel emissions systems on the Astra K 1.6 CDTi.

• Improves Emissions Accuracy: Helps the ECU measure and adjust fuel injection and exhaust treatment systems more accurately, reducing NOx output and helping maintain compliance with emissions standards.

• Restores Engine Performance: When NOx sensors fail, you may experience rough running, reduced fuel economy and limp-home modes — replacing both sensors helps eliminate these faults and supports smooth operation.

• Durable Design for Diesel Applications: Built to withstand high exhaust temperatures and long-term exposure to diesel combustion by-products common in turbo-diesel engines.

Frequently Asked Questions (FAQs)

Q1: What exactly do NOx sensors do?
A: NOx sensors measure the concentration of nitrogen oxides in the exhaust stream and send that information to the vehicle’s ECU. This helps the engine adjust combustion and exhaust treatment systems to reduce harmful emissions and improve engine efficiency.

Q2: Why am I replacing two sensors?
A: Modern diesel engines typically use two NOx sensors: one before and one after the catalytic converter / SCR system to monitor how effectively NOx emissions are being reduced. For accurate emissions control and fault diagnosis, both are replaced together when worn or faulty.

Q3: Which vehicles are these sensors compatible with?
A: This paired NOx sensor set is commonly fitted to Vauxhall/Opel Astra K 1.6 CDTi diesel models produced roughly from 2015–2022 with the B16 engine family. Always verify compatibility with your old part number or VIN.

Q4: What are signs the NOx sensors are faulty?
A: Symptoms include the check engine light, emissions test failure, rough idle, reduced fuel economy or decreased engine power — often caused by inaccurate NOx readings or sensor failure.

Q5: Is this pair easy to install?
A: Replacing NOx sensors involves accessing the exhaust manifold and downstream exhaust pipe areas, so while doable for experienced DIYers, professional installation is recommended to ensure correct sensor calibration and to clear any ECU fault codes.