Exhaust emission warning light Golf 2L

[PhilipBaker]

We've got a W reg Golf 2 litre Estate & the exhaust emission warrning light has just started to light up when we turn on the ignition, but it goes out when we start the engine. The fuel economy is also pretty poor approx 25-30MPG.

Can anyone provide some clues as to what the problem could be ?

[dainton]

Lambda sensor also known as the oxygen sensor. Should be quite cheap to fix.

[PhilB17]

Just taken the car to the VW garage for a diagnostic check & it did not identify the fault, but they stated that its probably a sensor. The local VW franchise said that a Lamda sensor is £91 + VAT & they asked whether it was the one after the CAT? What does that mean, where is the sensor. Several other posts stated that their emmission light came on but the cause was a faulty temperature sensor approx £25.

What the most likely cause, if it is still the lamda sensor does anyone know a cheaper source?

Cheers Phil.

[Mook]

There is one sensor before and one afterwards - one measures the CO emissions before they go through the cat and one measures it after they've passed through it and they both send the info to the ECU. The light comes on if either your cat is FUBARd, or if the sensor is knackered.

You might get a lambda sensor from German Swedish and French, but the price difference is not likely to be that much.

HTH

[mulkbear]

It is a commonly known fault for the Beetle 2.0 engines(same as yours) to burn out lambda probes but normally i recommend both Lambda sensors are changed as the other lambda probe normally goes a few hundred miles later.