M18x1.5 Auto Oxygen Sensor 7700103504 For Dacia Nissan Renault Citroen Peugeot Opel Vauxhall Proton

• This is a 4-wire heated zirconium oxide oxygen sensor, manufactured to original equipment standards for the Renault–Nissan–Dacia–Lada Alliance. The four wires serve two independent circuits — two for the internal heater (power and ground) and two for the sensor signal and signal ground.

• The built‑in heating element brings the ceramic sensing tip up to operating temperature quickly after a cold start, enabling the ECU to enter closed‑loop fuel control sooner and significantly reduce cold‑start emissions.

• The sensor is constructed with a stainless‑steel shell that resists rusting and provides greater durability under harsh exhaust environment conditions. The centre ceramic element is composed of Zirconium Oxide, Alumina and Yttrium Oxide. The platinum coating is applied using vapour deposition to ensure an even application, whilst a Spinel coating on the outer platinum layer prevents solid particles in the exhaust gas from damaging the component.

• As a diagnostic probe (downstream / post‑catalyst sensor), it is installed after the catalytic converter. Its primary function is to monitor the efficiency of the catalytic converter by comparing its signal with that of the upstream (pre‑catalyst) sensor.

• Under rich (excess fuel) conditions, the sensor outputs approximately 0.6 – 1.0 V. Under lean (excess oxygen) conditions, the output falls to near 0 V. The ECU uses this feedback to evaluate converter performance.

• As a direct‑fit sensor, it features a vehicle‑specific electrical connector (oval, 4‑pin) and pre‑terminated wiring, eliminating the need for cutting or splicing during installation.

• All sensors are 100% tested to meet or exceed original equipment quality standards.

Specification data compiled from multiple aftermarket catalogues (Fuel Parts LB1517, Lemark LLB232, Intermotor 64289, Febi 177414, CI XLOS1228). Physical specifications may vary slightly by manufacturer. Always compare the replacement sensor with your original part before installation.

This Lambda Sensor is an original equipment component for vehicles manufactured under the Renault–Nissan–Dacia–Lada Alliance. The following OE numbers are directly interchangeable. Always verify physical fitment (connector shape, cable length and thread size) with your original part before purchasing.

• The primary OE number for this component is 7700103504, with 7700109844 and 7700875342 being common alternative Renault/Dacia references.

• For NISSAN vehicles, the equivalent OE numbers include 7700103504, 7700109844 and 2269000QAE.

• For CITROËN and PEUGEOT vehicles, the OE reference is 6LS001.

• For OPEL / VAUXHALL, the reference numbers 4408954 and 91160174 are cross‑referenced to this OE number.

• The number 6001543615 is a Renault alternative reference found on compatible vehicles.

• The same OE number (7700103504) is also listed for PROTON vehicles under reference 7700107433.

• Important: This OE number has been documented as superseded by some manufacturers (e.g., PIERBURG indicates 7.05270.56.0 has been replaced by 7.05271.82.0).

• Always physically compare your old sensor‘s connector shape (oval), pin count (4), cable length, and thread size (M18 × 1.5) before purchasing.

This Lambda Sensor is an original equipment component for vehicles manufactured under the Renault–Nissan–Dacia–Lada Alliance, as well as certain Citroën, Peugeot, Opel, and Proton vehicles. Based on extensive cross‑reference data from multiple aftermarket catalogues, the sensor is used as a downstream / diagnostic (post‑catalyst) oxygen sensor on a wide range of 4‑cylinder petrol engines.

⚠️ Important Position Note: This is a downstream (post‑catalyst) oxygen sensor — installed after the catalytic converter. It should not be used in the upstream (pre‑catalyst) position unless your vehicle’s original sensor was located there. Upstream and downstream O₂ sensors are not interchangeable on most vehicles.

• For most applications (Dacia Logan, Sandero, Duster; Renault Megane; Nissan Kubistar; Opel/Vauxhall; Citroën/Peugeot; Proton), this is a downstream (post‑catalyst) oxygen sensor. It is installed after the catalytic converter (Bank 1, Sensor 2) and serves as a diagnostic probe for catalyst efficiency monitoring.

• Contrary application — Renault Safrane B54 (1992‑1997): On the Safrane, this same OE number is listed as an upstream (pre‑catalyst) regulating probe located in front of the catalyst. If your vehicle is a Renault Safrane of this era, the sensor will be installed before the catalytic converter.

• How to verify: Locate your vehicle‘s catalytic converter. The downstream sensor is installed in the pipe after the catalytic converter — follow the exhaust pipe from the rear of the converter to find the sensor. The upstream sensor is installed in the exhaust manifold or in the pipe before the converter. If your faulty sensor is located after the converter, this part is suitable for most applications listed above. If located before the converter, confirm that your vehicle is a Renault Safrane B54 or a similar early‑1990s application before ordering.

• Engine codes confirmed compatible (Dacia/Logan): K4M 690, K4M 697, K4M 698, K4M 696, K4M 694 (1.6L); K7J 710, K7J 714 (1.4L).

• Engine codes confirmed compatible (Renault Megane): 1.6L petrol variants.

• Engine codes confirmed compatible (Nissan Kubistar): 1.2L 16V petrol.

• Not compatible with diesel engines unless your vehicle originally used this sensor. Most diesel O₂ sensors (where fitted) use wideband (LSU) technology with different calibration parameters and part numbers.

• The vehicle fitment information above is a guide only. Always confirm compatibility using your vehicle‘s VIN or by physically inspecting your old sensor‘s position (upstream vs. downstream), connector shape (oval), cable length, and thread size (M18 × 1.5) before ordering.

A faulty downstream (post‑catalyst) oxygen sensor degrades the ECU‘s ability to accurately monitor catalytic converter efficiency. While the engine may still run normally, emissions, fuel economy and OBD‑II readiness are all negatively affected. Replace your lambda sensor immediately if you experience any of the following symptoms.

• Normal wear and tear — Lambda sensors typically degrade after 100,000 – 160,000 km (60,000 – 100,000 miles) of operation due to continuous exposure to high‑temperature exhaust gases (300°–700° F) and thermal cycling stress. The recommended replacement interval for this sensor is 160,000 km.

• Heater circuit failure — The internal heating element opens or shorts. This causes the sensor to respond extremely slowly or not at all when cold, triggering P0036‑P0037 codes.

• Contamination (“sensor poisoning”) — Oil, coolant (head‑gasket leaks), silicone‑based sealants, or the use of leaded fuel permanently coats the ceramic sensing tip, destroying its ability to detect oxygen. Carbon‑clogging is also a common cause of failure.

• Physical impact damage — Dropping the sensor (even from a low height) or impact from road debris can crack the fragile ceramic element.

• Wiring / connector issues — Damaged wiring, loose connections, corrosion at the connector, or an intermittent open / short circuit can trigger fault codes even when the sensor itself is healthy.

• Exhaust leaks near the sensor bung — False oxygen readings from an exhaust leak will cause erratic sensor output and may be incorrectly attributed to a faulty sensor.

• Aging due to long‑term use — Extended exposure to high‑temperature exhaust gases degrades the sensing element over time.

• P0420 (Catalyst System Efficiency Below Threshold) is the most common code associated with downstream sensor failure. However, P0420 can also indicate a failing catalytic converter.

• How to differentiate: If the downstream sensor‘s voltage readings are too similar to those of the upstream sensor (both fluctuating rapidly), the catalytic converter is likely no longer functioning properly. If the downstream sensor voltage is stuck high, stuck low, or shows no activity, the sensor itself is likely faulty.

• If your MIL is on but your vehicle is driving normally, you should still have the fault codes checked, as a failed downstream sensor could be increasing fuel consumption without noticeable driveability symptoms.

• To diagnose a faulty sensor:

  • Heater circuit test: Use a digital multimeter to measure the resistance across the two heater circuit pins. An open circuit (infinite resistance) or short circuit (0 Ω) indicates heater failure.

  • Sensor signal test: Use an OBD‑II scanner to monitor the downstream sensor voltage output under steady‑state driving. A healthy downstream sensor should show a relatively stable voltage signal that is distinct from the upstream sensor‘s fluctuating output.

• Important: Do not interchange the upstream (pre‑catalyst) oxygen sensor with the downstream (post‑catalyst) sensor, as this will result in implausible fault entries.

• DO NOT use spray, grease, fluid or similar products on the oxygen sensor plug connections, as these can interfere with signal transmission.

• Always investigate the root cause before replacing the sensor — if contamination caused the failure, replacing the sensor without addressing the underlying issue will result in repeated premature failure.

Fault code information based on OBD‑II standardised diagnostic trouble code definitions and automotive diagnostic resources. Symptom information compiled from manufacturer technical documentation and product listing data.

• This is a direct‑fit downstream sensor with an oval 4‑pin connector, 250 – 475 mm cable length (depending on manufacturer — Fuel Parts LB1517: 250 mm; Intermotor 64289: 455 mm; CI XLOS1228: 475 mm), M18 × 1.5 thread, and 22 mm (7/8″) spanner size.

• ⚠️ Do not purchase based solely on the OE number. Aftermarket equivalents may have significant differences in cable length, connector shape, or calibration parameters. If the connector does not match, do not install.

• Physically compare your original sensor‘s connector shape (oval), pin count (4), cable length, and thread size (M18 × 1.5) before ordering.

• Measure the cable length of your original sensor. Documented cable lengths for this OE number include 250 mm, 455 mm, and 475 mm. A significant mismatch may cause routing difficulties or the connector failing to reach the harness.

• For most applications (Dacia Logan, Sandero, Duster; Renault Megane; Nissan Kubistar; Opel/Vauxhall; Citroën/Peugeot; Proton), this sensor is designed for the downstream (post‑catalyst / rear) position as a diagnostic probe (Bank 1, Sensor 2). It should be installed after the catalytic converter.

• Contrary application — Renault Safrane B54 (1992‑1997): On the Safrane, this OE number is listed as an upstream (pre‑catalyst) regulating probe. If your vehicle is a Renault Safrane of this era, the sensor will be installed before the catalytic converter.

• Upstream and downstream O₂ sensors are not interchangeable in most vehicles. Replacing an upstream sensor with a downstream unit (or vice versa) will result in improper ECU readings, persistent fault codes, and the ECU may not be able to correctly monitor catalyst efficiency.

• How to verify: Locate your vehicle‘s catalytic converter. The downstream sensor is installed in the pipe after the catalytic converter — follow the exhaust pipe from the rear of the converter to find the sensor. The upstream sensor is installed before the converter. If your faulty sensor is located after the converter, this part is suitable for most applications listed above. If located before the converter and your vehicle is not a Renault Safrane B54, this part may not be suitable.

• For Dacia Logan 2005 with K7M‑F710 engine, forum discussions confirm that 7700103504 is one of the possible OE numbers for the downstream sensor, but checking with your VIN is recommended as 6001549061 may also apply.

• Lambda sensors degrade gradually over time, often without triggering immediate fault codes. Their switching response becomes slower and their voltage range narrows with age and mileage.

• Proactive replacement at 160,000 km (approx. 100,000 miles) is recommended to maintain optimal catalytic converter health, proper emissions output, and correct OBD‑II monitor readiness.

• Even if no Check Engine Light is present, an aged sensor will still respond more slowly than a new one, affecting catalyst monitoring accuracy. Proactive replacement can help prevent premature catalytic converter failure — a much more expensive repair than the sensor itself.

• This OE number has been superseded by some manufacturers (e.g., PIERBURG indicates 7.05270.56.0 has been replaced by 7.05271.82.0).

• Replacement parts compatible with this OE number include PIERBURG 7.05270.56.0 and PIERBURG 7.05271.82.0.

• Aftermarket equivalents (e.g., Fuel Parts LB1517, Lemark LLB232, Febi 177414, CI XLOS1228, Kerr Nelson KNL286, Intermotor 64289) are widely available and meet or exceed OE quality standards.

• VDO / Continental also list this OE number for Renault Safrane applications.

• Allow the exhaust system to cool completely before removal — the catalytic converter remains dangerously hot for up to 30 minutes after engine shutdown. Attempting removal on a hot system risks severe burns.

• Disconnect the vehicle‘s battery negative (-) cable before starting work to prevent electrical issues, potential ECU damage, or accidental short circuits.

• Use a high‑quality O₂ sensor socket (22 mm / 7/8″) with an offset design to prevent stripping the sensor‘s flats and to provide better access in confined underbody areas. A standard deep socket can easily damage the sensor housing or its flats.

• Apply penetrating oil (e.g., WD‑40) to the threads of the old sensor the night before removal. This can significantly ease extraction, especially if the sensor has been installed for many years in the harsh exhaust environment.

• If the sensor is difficult to remove when cold, it may be easier when the exhaust is warm (run the engine for 1‑2 minutes, then allow it to cool until it is warm but not scalding). Exercise extreme caution to avoid burns — wear heavy‑duty heat‑resistant work gloves.

• Do not use excessive force — damage to the exhaust bung threads can result in expensive repairs, potentially requiring exhaust component replacement or thread repair (helicoil / timesert).

• Disconnect the electrical connector carefully — press the locking tab and pull only the connector housing (never pull directly on the wires). Follow the sensor wires to locate the connector, which is typically secured to a bracket on the engine block or underbody.

• Inspect the old sensor‘s connector, cable, and tip for signs of contamination (oil, soot, coolant residue), melting, or cracking. Note any contamination — this indicates an underlying engine issue that must be addressed before installing the new sensor to prevent repeat failure.

• Do not apply additional anti‑seize compound unless the new sensor‘s threads are completely dry. Many OE‑quality sensors are factory‑coated with anti‑seize. Adding extra can contaminate the sensor tip and cause premature failure. If the threads appear dry and no pre‑grease is evident, apply a small amount of sensor‑safe anti‑seize compound to the threads only — never to the sensor tip.

• Do not use silicone sealants anywhere near the exhaust system — silicone vapour will permanently contaminate and destroy the oxygen sensor (this is one of the most common causes of premature failure and is almost always non‑warrantable).

• Avoid touching the sensor tip — skin oils contain salts and contaminants that can damage the ceramic sensing element, causing inaccurate readings and premature failure. Always handle the sensor by the hexagon nut or connector body.

• Do not drop the sensor — the ceramic element inside the metal housing is brittle and can crack upon impact, rendering the sensor inoperative even if no external damage is visible.

• Tighten to the correct torque — typical torque for an M18 × 1.5 oxygen sensor is 40 – 50 Nm (30 – 37 ft‑lb). Some manufacturers specify 28 Nm or 41 Nm — always refer to your vehicle‘s service manual for the exact specification. Use a torque wrench to avoid overtightening or undertightening.

  • CAUTION: Overtightening can damage threads in the exhaust bung and may crack the sensor housing. Undertightening may cause exhaust leaks and false oxygen readings.

• Route the wiring harness securely using the original clips and routing guides to prevent contact with hot exhaust components (catalytic converter, exhaust pipe) or moving parts (drive shafts, steering components). Use zip ties if original clips are missing or damaged, but ensure they are rated for high‑temperature underbody use.

• Reconnect the electrical connector fully — an audible click confirms correct engagement. Ensure the locking tab is fully seated and locked into place.

• DO NOT use spray, grease, fluid or similar products on the oxygen sensor plug connections — these can interfere with signal transmission and cause electrical faults.

• Reconnect the vehicle‘s battery after installation is complete.

• Start the engine and allow it to reach normal operating temperature (closed‑loop mode). This typically takes 5‑10 minutes of driving or idling.

• Verify that no exhaust gas leakage exists around the sensor bung (listen for “puffing” sounds, or use a soap‑and‑water solution sprayed around the threads — bubbles indicate a leak).

• Use an OBD‑II scanner to clear any existing fault codes (old codes stored in the ECU must be cleared to turn off the MIL and reset monitors).

• Drive the vehicle through a complete drive cycle (typically 10‑20 minutes of mixed driving: stop‑start traffic, steady cruising at 50‑60 mph, moderate acceleration and deceleration) to allow the ECU to re‑learn adaptation values and complete oxygen sensor and catalyst monitors.

• After the drive cycle, re‑scan for fault codes to confirm that the oxygen sensor monitors have completed and that no new codes have appeared.

• While this is a direct‑fit part, professional installation is strongly recommended if you are not experienced with exhaust system work or if the sensor is located in a difficult‑to‑reach position (e.g., on the underbody requiring vehicle lifting).

• After replacement, the ECU may need to have adaptation values reset using manufacturer‑specific diagnostic equipment (e.g., Renault CLIP, Dacia diagnostic tools, Nissan CONSULT).

• Improper installation can lead to:

  • Exhaust leaks around the sensor bung

  • Cross‑threaded or damaged exhaust bung threads — expensive to repair, possibly requiring exhaust pipe replacement

  • Sensor damage from contamination or mishandling (touching tip, dropping, silicone exposure)

  • Wiring damage from contact with hot exhaust components or moving parts

  • Persistent ECU fault codes despite a correctly functioning sensor

• Aftermarket equivalents (sold by brands such as Fuel Parts, Lemark, Kerr Nelson, Intermotor, Febi, CI) may offer varying warranty periods — commonly 1 to 5 years. For example:

  • Fuel Parts LB1517: 2‑year warranty

  • Lemark LLB232: 5‑year warranty

  • COWTOTAL: 1‑year warranty

• Check with your specific retailer for their warranty terms and return policy.

• Important: Most warranties are voided if the sensor tip shows contamination from improper handling (e.g., touching the tip, dropping the sensor, silicone exposure, or installation with contaminated hands or tools). Oxygen sensors are often non‑returnable except for approved warranty replacement due to contamination risk.

• Keep your original packaging until the new sensor is installed and confirmed working — you may need it for warranty claims or returns.