T4 Lambda Sensor - 2.5 Petrol

This heated lambda (oxygen) sensor is designed to fit before the catalytic converter on petrol VW models. It continuously measures the oxygen content in the exhaust gases and feeds real-time data to the ECU, allowing precise adjustment of the air–fuel mixture. This ensures smooth running, correct emissions, and optimal fuel economy, particularly during cold starts when the built-in heater brings the sensor up to operating temperature quickly.

A failing pre-cat lambda sensor can cause poor MPG, rough idle, hesitation, engine management light faults, and MOT emission failures. This direct-fit, 4-pin replacement restores correct engine management operation without modification.

Technical Details

• Sensor type: Heated oxygen (lambda) sensor

• Fitting position: Before catalytic converter (pre-cat)

• Number of pins: 4

• Cable length: 780 mm

• Fuel type: Petrol

Vehicle & Engine Fitment

VW Transporter T4

• 2.5 Petrol – Engine codes AEU, AEN, ACU, AAF (11/1990–06/2003)

• 2.5 Petrol – Engine code AET (08/1996–06/2003)
  (Bus, Van & Platform/Chassis)

VW Golf Mk3

• 2.0 Petrol – 115 PS (Hatchback & Estate)

• 2.8 VR6 Petrol – 174 PS (Hatchback)

VW Passat B3/B4

• 2.0 Petrol – 107–116 PS (Saloon & Estate)

VW Polo Classic 6V2

• 1.6 Petrol – 100 PS (Saloon)

VW Sharan I

• 2.0 Petrol – 115 PS

VW Vento

• 2.0 Petrol – 115 PS

• 2.8 VR6 Petrol – 174 PS

• 1.6 Petrol – 101 PS

Fitment Notes

• Pre-catalyst sensor only – do not confuse with post-cat monitoring sensors

• Check engine code and plug style before ordering

• Sealing washer usually supplied; renew if required