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9A790626550/1
Product Information
Product Information
Lambda Oxygen Sensor, AFTER Catalytic Converter.

Restore accurate exhaust monitoring and dependable emissions-system operation with this OE Match Lambda Oxygen Sensor. Designed for compatible Porsche applications, this sensor is installed AFTER the catalytic converter, where it monitors oxygen levels in the exhaust gases after they have passed through the catalyst.

Fits:

  • Porsche 971.1 Panamera V6 3.0L 2WD (330 Hp) 2017-20
  • Porsche 971.1 Panamera 4 V6 3.0L 4WD (330 Hp) 2017-20
  • Porsche 971.1 Panamera 4 V6 3.0L 4WD Executive 2017-20
  • Porsche 971.1 Panamera 4 3.0L Turbocharged V6 Sport Turismo 2017-20
  • Porsche 971.1 Panamera 4S V6 3.0L 4WD (440 Hp) 2017-20
  • Porsche 971.1 Panamera 4S V6 3.0L 4WD Executive 2017-20
  • Porsche 971.1 Panamera 4S 2.9L Twin-Turbo V6 Sport Turismo 2017-19
  • Porsche 971.1 Panamera Turbo V8 4.0L 4WD (550 Hp) 2017-18
  • Porsche 971.1 Panamera Turbo V8 4.0L 4WD Executive 2017-18
  • Porsche 971.1 Panamera Turbo 4.0L Twin-Turbo V8 Sport Turismo 2017-18  

Diagram Ref No 18

Also known as an oxygen sensor, O2 sensor or lambda probe, the downstream lambda sensor provides important feedback to the engine control unit (ECU). Its primary role is to help the vehicle monitor the performance of the catalytic converter and identify abnormal exhaust or emissions-system behaviour.

The ECU can compare signals from sensors positioned before and after the catalytic converter. This information helps determine whether the catalyst is treating the exhaust gases as expected.

Operating directly in the exhaust system exposes the sensor to high temperatures, vibration, moisture, combustion deposits and repeated thermal cycling. With age, the sensing element can become contaminated or slow to respond, while the internal heater, electrical connector or wiring may also deteriorate.

This OE Match Lambda Oxygen Sensor provides a high-quality replacement for a slow, inaccurate or failed downstream sensor.


What This Product Does:

  • Measures oxygen content in the exhaust gases.
  • Operates AFTER the catalytic converter.
  • Sends exhaust oxygen information to the ECU.
  • Helps monitor catalytic converter performance.
  • Allows comparison with upstream lambda sensor readings.
  • Supports emissions-system diagnostics.
  • Helps detect abnormal catalytic converter behaviour.
  • Provides feedback on downstream exhaust conditions.
  • Supports reliable engine-management monitoring.
  • Helps identify emissions-system faults.
  • Works with the vehicle's wider exhaust and emissions-control system.
  • Replaces a slow, contaminated or failed downstream oxygen sensor.
  • Restores reliable catalyst-monitoring information when sensor failure is confirmed.  

Symptoms Of Wear Or Failure:
  • Check engine or engine-management warning light.
  • Oxygen sensor-related diagnostic fault codes.
  • Downstream lambda sensor fault codes.
  • Catalyst-efficiency-related fault codes.
  • Emissions-system warning messages.
  • Slow oxygen sensor response.
  • Implausible downstream sensor readings.
  • Intermittent sensor signals.
  • Sensor reading remaining unusually fixed.
  • Vehicle failing an emissions test.
  • Increased exhaust emissions.
  • Sensor heater circuit fault.
  • Open- or short-circuit sensor faults.
  • Damaged sensor wiring.
  • Heat-damaged wiring insulation.
  • Corroded or damaged electrical connector.
  • Physical damage to the sensor.
  • Sensor seized into its exhaust mounting point.  

Why Replacement Matters:
  • The downstream oxygen sensor is an important part of the vehicle's emissions-monitoring system.
  • While a before-catalyst sensor is generally more directly involved in air-fuel mixture control, the after-catalyst sensor primarily allows the ECU to monitor the behaviour and efficiency of the catalytic converter.
  • If the downstream sensor becomes slow, inaccurate or completely inoperative, the ECU may no longer receive trustworthy information about exhaust conditions after the catalyst.



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