11787548961 Downstream O2 Sensor Post-Cat 234-4488 1618V3 MINI Cooper AKAS

The AKAS Downstream O2 Oxygen Sensor (OEM Part Number: 11787548961) is a direct-fit replacement for the rear oxygen sensor located AFTER the catalytic converter on MINI Cooper, Cooper S, and JCW models equipped with the 1.6L N14 or N18 turbocharged engine - including the R55 Clubman, R56 Hatch, R57 Convertible, R58 Coupé, R59 Roadster, R60 Countryman, and R61 Paceman chassis (model years 2005-2016). This downstream (post-catalytic / after cat / Bank 1 Sensor 2) sensor monitors the efficiency of the catalytic converter by measuring the oxygen content in the exhaust gas AFTER it has passed through the catalyst - restoring proper catalytic converter efficiency monitoring, clearing common engine fault codes (P0136, P0138, P0140, P0420, P0430), and returning your MINI's fuel economy and engine performance to normal.

1. OEM Part Number 11787548961 - Downstream Post-Cat Sensor This is the downstream (post-catalytic / after cat / Bank 1 Sensor 2) oxygen sensor located AFTER the catalytic converter in the exhaust pipe - OEM part number 11787548961, NOT the upstream/pre-cat sensor (upstream part number is typically 11787537984, 11787590713, or similar); verify your original sensor part number before purchasing, and confirm you need the downstream (Bank 1 Sensor 2) sensor, not the upstream (Bank 1 Sensor 1) sensor.

2. Direct Fit Replacement - No Cutting or Wiring Modification Manufactured to OEM-equivalent specifications with a high-quality zirconium dioxide sensing element that provides accurate, fast-responding oxygen level readings to the ECU - featuring a durable stainless steel housing, heat-resistant PTFE wiring, and a factory-fitted 4-pin electrical connector that matches the original MINI wiring harness exactly; no cutting, splicing, or wiring modification required, simply locate the downstream sensor after the catalytic converter, disconnect the old sensor, unscrew it, apply anti-seize compound (pre-applied on most aftermarket sensors), screw in the new sensor by hand, tighten to 40-50 Nm, reconnect the connector, and clear fault codes with an OBD2 scan tool.

3. Restores Catalytic Converter Monitoring & Clears Fault Codes The downstream sensor's primary function is to monitor the efficiency of the catalytic converter by measuring oxygen content in exhaust gas AFTER it has passed through the catalyst - the ECU/DME compares upstream (before cat) and downstream (after cat) sensor readings; if the catalytic converter is working correctly, the downstream sensor reading should be much more stable and show significantly less oxygen fluctuation than the upstream sensor; a failed downstream sensor (due to aging, oil/coolant/fuel additive contamination, or physical damage beyond threshold) triggers the check engine light with common fault codes P0136, P0138, P0140 (downstream sensor circuit malfunction), P0420, P0430 (catalytic converter efficiency below threshold) - this replacement sensor restores proper catalytic converter efficiency monitoring, clears the engine fault codes, and returns your MINI's fuel economy and engine performance to normal.

4. Wide MINI Compatibility - R55 to R61, N14 & N18 Engines Designed specifically for MINI Cooper/Cooper S/JCW models equipped with the 1.6L N14 (2007-2010) or N18 (2010-2016) turbocharged engine - compatible chassis codes include R55 Clubman, R56 Hatch, R57 Convertible, R58 Coupé, R59 Roadster, R60 Countryman, and R61 Paceman (model years 2005-2016); thread size M18×1.5 (standard oxygen sensor thread), torque specification 40-50 Nm, entire installation takes approximately 20-40 minutes with basic tools - a 22mm oxygen sensor socket (or 7/8 inch wrench with a slot for the wire), a jack and axle stands (or a vehicle lift), and an OBD2 scan tool to clear fault codes; professional installation by a qualified auto electrician or mechanic is recommended, especially if you are not familiar with automotive exhaust and electrical systems.

5. Quality Construction & 6-Month Warranty - South Africa Ready Built with high-quality zirconium dioxide sensing element, durable stainless steel housing, heat-resistant PTFE wiring, and factory-fitted electrical connector - designed to withstand the extreme high temperatures of the exhaust system (operating range up to 400-600 C); package includes 1 X Oxygen Sensor After Kat, everything you need for replacement; backed by a 6-month limited warranty covering manufacturing defects (sensing element failure, heating element failure, electrical connector defects, wiring insulation failure, thread defects) under normal use and correct installation; in stock in South Africa (CPT JHB) with free next-day delivery, eligible for cash on delivery, hassle-free exchanges & returns for 30 days, and dedicated after-sales support from AKAS SHOP (Seller Score 4.7, 120 Reviews) - the smart, affordable solution for restoring your MINI's exhaust emission monitoring system and clearing that persistent check engine light.

Product Specifications

OEM Part Number: 11787548961

Sensor Type: Downstream O2 Oxygen Sensor / Post-Catalytic Lambda Sensor / After Kat Sensor

Position: AFTER the catalytic converter (Bank 1 Sensor 2 / Post-Cat / Downstream)

Compatible Brand: MINI (BMW Group)

Compatible Models: MINI Cooper, Cooper S, Cooper One, JCW

Compatible Chassis: R55 Clubman, R56 Hatch, R57 Convertible, R58 Coupé, R59 Roadster, R60 Countryman, R61 Paceman

Compatible Engine: 1.6L N14 (2007-2010), N18 (2010-2016) turbocharged

Model Years: 2005-2016

Sensing Element: High-quality zirconium dioxide

Housing Material: Durable stainless steel

Wiring: Heat-resistant PTFE wiring

Electrical Connector: Factory-fitted 4-pin rectangular connector (matches original MINI harness)

Thread Size: M18×1.5 (standard oxygen sensor thread)

Torque Specification: 40-50 Nm

Installation: Direct fit replacement - no cutting, splicing, or wiring modification required

Common Fault Codes: P0136, P0138, P0140 (downstream sensor circuit), P0420, P0430 (catalytic converter efficiency)

NOT Compatible: Upstream/pre-cat sensor (upstream part number typically 11787537984, 11787590713, or similar)

Package Includes: 1 X Oxygen Sensor After Kat

Warranty: 6-month limited warranty

Verify Compatibility Before Purchase: This is the downstream (post-cat / Bank 1 Sensor 2) sensor with OEM part number 11787548961 - NOT the upstream/pre-cat sensor; verify your original sensor part number on the sensor body or connector, confirm by VIN, and confirm you need the downstream (Bank 1 Sensor 2) sensor, not the upstream (Bank 1 Sensor 1) sensor, before purchasing.

Safety Warning - Hot Exhaust Components: The oxygen sensor is installed in the exhaust system which operates at extremely high temperatures (exhaust pipe and sensor can reach 400-600 C after driving, and even after 30 minutes the engine is off may still be hot enough to cause severe burns) - NEVER attempt to remove or install the oxygen sensor immediately after driving, wait at least 1-2 hours after the engine has been turned off to allow the exhaust system to cool completely, always wear insulated gloves when handling the exhaust pipe and sensor even after cooling, and always use a jack and axle stands (or a vehicle lift) when lifting the vehicle - NEVER work under a vehicle supported only by a jack.

Professional Installation Recommended: While this is a direct-fit replacement part that can be installed by a competent DIY enthusiast with basic mechanical skills and the right tools, professional installation by a qualified auto electrician, MINI specialist, or automotive mechanic is highly recommended - incorrect installation (including cross-threading, over-tightening, under-tightening, damaging the electrical connector pins, or cracking the sensor ceramic element) may result in sensor failure (voiding the warranty), exhaust port thread damage (requiring expensive thread repair using a helicoil thread insert kit), exhaust leaks (causing inaccurate sensor readings, increased noise, and potential emissions test failure), persistent check engine light, or electrical short circuit from damage to the ECU/DME.

OBD2 Scan Tool Required to Clear Fault Codes: After installing the new oxygen sensor, you MUST clear the existing fault codes from the engine control unit (ECU/DME) using an OBD2 scan tool - simply installing the new sensor will NOT automatically turn off the check engine light, the ECU stores the fault codes in its memory and will keep the code illuminated until manually cleared; a basic OBD2 code reader (available from auto parts stores) can clear generic OBD2 fault codes (P00xx such as P0136, P0138, P0140, P0420), but MINI-specific fault codes (such as 29E1, 29E2, 29E3) may require a more advanced scan tool (such as INPA/ISTA setup, Foxwell NT510, Autel MaxiCOM, or similar MINI-compatible diagnostic tools); after clearing the codes, you must drive the vehicle for at least 15-20 minutes (including a mix of city and highway driving) to allow the ECU to complete the oxygen sensor and catalytic converter monitoring "drive cycles".

Seized Sensor Removal - Use Penetrating Oil: On MINI vehicles with 100,000+ km, especially in coastal areas (Cape Town, Durban, Port Elizabeth) where salt air accelerates corrosion, the old oxygen sensor may be seized in the exhaust port due to heat-induced corrosion and galvanic reaction between the cast iron/stainless steel exhaust port - if the sensor does not loosen with moderate force using a 22mm oxygen sensor socket, DO NOT apply excessive force as this can round off or break the sensor body; instead, apply a generous amount of penetrating oil (such as WD-40, CRC 5-56, Q20, or dedicated penetrating oil like Kroil or PB Blaster) to the sensor threads and surrounding exhaust port area, allow the oil to soak for at least 10-15 minutes (longer is better - soak overnight if possible), then try loosening the sensor with a longer wrench or impact wrench applying steady, even pressure - do NOT use an impact wrench or hammer as this can damage the sensor or exhaust; if the sensor is still seized, you may need to use a nut splitter or specialized oxygen sensor removal tool, and in extreme cases the sensor threads may be damaged during removal requiring thread repair with a helicoil (thread insert) kit (M18×1.5 size) before installing the new sensor.

Anti-Seize Compound - Do NOT Contaminate Sensing Element: This oxygen sensor comes with anti-seize compound pre-applied to the threads - if you need to apply additional anti-seize (for example, if the pre-applied compound has been wiped off or contaminated), use ONLY a copper-based or nickel-based anti-seize compound specifically designed for oxygen sensor threads (do NOT use regular grease, oil, or general-purpose anti-seize that may contain metals that can poison the sensor); apply only a THIN layer to the threads only (for example, do NOT allow anti-seize to come into contact with the sensor's sensing element (the slotted metal tip that goes into the exhaust stream), the protection tube holes, or the electrical connector pins) - contamination of the sensing element with anti-seize compound, grease, oil, or other substances will poison the zirconium dioxide sensing element, causing inaccurate readings, slow response, or complete sensor failure, and this contamination damage is NOT covered by the warranty; if you accidentally get anti-seize on the sensing element, do NOT attempt to clean it with solvents, wire brushes, or abrasives as this will further damage the sensor - contact us for a replacement.

Do NOT Use Universal Oxygen Sensors: This is NOT a universal oxygen sensor - this is a direct-fit oxygen sensor with a factory-fitted MINI-specific electrical connector; do NOT cut the connector or attempt to modify the wiring, and do NOT purchase a "universal" oxygen sensor as a substitute - universal sensors require you to splice/solder the wires to your old connector, which introduces potential faults, corrosion points, and signal interference, and may not be compatible with the MINI ECU's signal requirements; if your vehicle's wiring harness connector is damaged or corroded, you may need to repair or replace the connector before installing this sensor, as a faulty connector can cause signal loss, inaccurate readings, or persistent fault codes even with a new sensor.

Warranty Limitations: We provide a 6-month limited warranty covering manufacturing defects (sensing element failure, heating element failure, electrical connector defects, wiring insulation failure, thread defects) under normal use and correct installation - the warranty does NOT cover: (1) damage caused by incorrect installation (cross-threading, over-tightening, under-tightening, forced connector insertion, wiring modification); (2) damage caused by contamination of the sensing element with anti-seize compound, grease, oil, fuel additives, coolant, silicone, or other foreign substances; (3) damage caused by excessive force, impact, dropping, or improper tool use during installation or removal; (4) damage caused by vehicle accidents, collisions, fire, or water submersion; (5) damage caused by exposure to temperatures beyond the specified operating range; (6) normal wear and tear of consumable components (the sensing element degrades over time and exposure to exhaust - this is normal wear, not a manufacturing defect; typical sensor lifespan is 80,000-150,000 km depending on driving conditions, fuel quality, and engine condition); (7) consequential damage to the vehicle or other components caused by sensor failure; (8) fault codes caused by other vehicle issues (upstream sensor failure, vacuum leaks, exhaust leaks, fuel system problems, ECU faults) that persist even after replacing the sensor; to make a warranty claim, please retain your original purchase receipt and contact us with photos of the defective sensor (showing the sensing element, connector, and any visible damage), the fault codes from your scan tool, and a description of the failure.

What's in the box
1 X Oxygen Sensor After Kat