55236779 Car Oxygen Sensor For Alfa Romeo / Abarth / Fiat / Lancia / Iveco / Ferrari / Chrysler / Dodge / Citroen / Peugeot / Tata

Pictures In Detail:

Technical Notes:

• This is a 4-wire heated oxygen sensor designed for precise air-fuel mixture control

• The heating element allows the sensor to reach operating temperature quickly, reducing cold-start emissions and improving fuel efficiency

• All sensors undergo 100% testing to ensure quality standards

This Lambda Sensor replaces the following Original Equipment Manufacturer (OEM) and interchange part numbers. Check your old sensor to confirm a match:

Interchange / Aftermarket Reference Numbers:

Note: Always verify physical fitment before purchasing, as aftermarket interchange numbers may not be identical in all applications.

This Lambda Sensor is primarily used in vehicles from the Fiat Group (Stellantis) , including Alfa Romeo, Fiat, Lancia, Abarth, and Iveco. It also has cross-brand compatibility with certain Chrysler, Dodge, Citroën, Peugeot, and Tata models.

Fitment Notes:

• This sensor is widely used across the Fiat-Chrysler (Stellantis) ecosystem

• Position (upstream/downstream) may vary by specific vehicle model and engine configuration

• Compatible with both petrol and Natural Power (CNG) engine variants

• Always verify with your vehicle's VIN and the position of your old sensor before ordering

Consider replacing your Lambda Sensor if you experience any of the following:

Check Engine Light (MIL) Illumination

• OBD-II fault codes related to oxygen sensor circuit:

  • P0130-P0167 series (O2 Sensor Circuit Malfunction)

  • P0420 / P0430 (Catalyst System Efficiency Below Threshold)

  • Manufacturer-specific codes for Fiat/Alfa Romeo/Lancia vehicles

Performance & Driveability Issues

• Incorrect mixture control – ECU receives inaccurate data, causing improper fuel trim adjustments

• Poor acceleration or hesitation – Engine struggles under load, especially noticeable in turbocharged models

• Rough idle or stalling – Unstable engine operation at low speeds

• Reduced engine power – Noticeable loss of performance

Fuel & Emissions Symptoms

• Increased fuel consumption – A faulty sensor can cause the engine to run rich, wasting fuel (potential savings up to 15% with replacement)

• Failed emissions test – Incorrect air-fuel ratio leads to high pollutant output

• Black smoke from exhaust – Indicates excessively rich mixture

• Strong fuel odour – Unburned fuel in exhaust

Potential causes of sensor failure:

• Normal wear and tear – Replacement is typically recommended every 100,000 miles (160,000 km)

• Contamination – Oil, coolant, or silicone sealants can damage the sensing element

• Heater circuit electrical failure – Internal heating element stops functioning

• Physical damage – Impact from road debris or improper handling during installation

• Exhaust leaks – Upstream or downstream leaks can affect sensor readings

1. Confirm Fitment Before Purchasing

• This is a direct-fit sensor with a specific 4-pin connector

• Always cross-reference your old sensor's part number, connector shape, and wire length before ordering

• Compatible with OEM numbers: 55236779, 55236778, 46474584, 46750245, 46751082

• Physical inspection of your original sensor is strongly recommended

2. Determine Position (Upstream vs. Downstream)

• This part number (55236779) may function as either a regulating sensor (upstream/pre-cat) or diagnostic sensor (downstream/post-cat) depending on the specific vehicle application

• Some applications (e.g., Fiat Uno/Palio 1.0-1.4) typically use this as a primary sensor

• Verify the location of your old sensor (Bank 1, Sensor 1 or 2) before ordering

3. Cross-Brand Compatibility Verification

• While this OE number is listed for Alfa Romeo, Fiat, Lancia, Abarth, and Iveco, connector designs may vary by vehicle model and year

• Also compatible with Chrysler, Dodge, Citroën, Peugeot, and Tata vehicles via cross-reference numbers

• For non-Fiat applications, confirm with your vehicle's manufacturer specifications

4. Replacement Interval

• Lambda sensors degrade over time, often without triggering immediate fault codes

• Replacement every 100,000 miles (160,000 km) is recommended to maintain:

  • Optimal fuel efficiency

  • Catalytic converter health and longevity

  • Proper emissions output

  • Smooth engine operation

5. Installation Tips

• Allow the exhaust system to cool completely before removal to avoid burns and prevent thread damage

• Use an O2 sensor socket (22mm or 7/8") to prevent stripping the sensor during removal/installation

• Apply anti-seize compound to the threads of the new sensor (avoiding the sensor tip) to prevent seizing in the exhaust bung

• Do not use silicone sealants near the exhaust system – contamination will destroy the sensor

• Avoid touching the sensor tip – oils from your skin can contaminate the sensing element

• Do not drop the sensor – the ceramic element can crack upon impact

• Tighten to the correct torque – Typically 40-50 Nm (30-37 ft-lb)

• Secure wiring harness with proper clips to prevent contact with hot exhaust components or moving parts

6. Required Tools

• O2 sensor socket (22mm / 7/8") or deep offset wrench

• Ratchet and extension bar (for access)

• Anti-seize compound (sensor-safe, if not pre-applied)

• Jack and jack stands (if under-vehicle access requires lifting)

• OBD-II scanner (to clear fault codes and verify operation after replacement)

7. Quantity Needed

• 4-cylinder engines typically have 1-2 oxygen sensors

• Some vehicles may require two sensors – one for each bank or position

• Check your vehicle's exhaust configuration to determine how many sensors you need

8. Warranty

• Quality Lambda Sensors typically come with a warranty period (e.g., 1 year)

• Aftermarket sensors may offer varying warranty terms

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

• Important: Warranties may be voided if the sensor tip shows contamination from improper handling