Lambda sensor?

hi we have a vw golf and the exhaust system light has just come on the manual says it is the lambda sensor, the car is due to go for a service and MOT at the end of this month, is it important that it goes in before or can it wait

Ruth Holden
July 2011

diesel then it will not have one

gsc
February 2009

Sorry mutley...

Since oxygen sensors are located in the exhaust stream, they do not directly measure the air or the fuel entering the engine. But when information from oxygen sensors are coupled with information from other sources, they can be used to indirectly determine the air-to-fuel ratio. Closed-loop feedback-controlled fuel injection varies the fuel injector output according to real-time sensor data rather than operating with a predetermined (open-loop) fuel map. In addition to enabling electronic fuel injection to work efficiently, this emissions control technique can reduce the amounts of both unburnt fuel and oxides of nitrogen from entering the atmosphere. Unburnt fuel is pollution in the form of air-borne hydrocarbons,

Peccavi reads Wikipedia and understands closed loop servo systems
February 2009

lamda sensors only produce a small varying voltage.dependant on the amout of oxegen in the pipe,after combustion,and tells ecu.lambda probes do not help poisons get burnt up.so unlikely to be a sensor fault,just ecu is getting a errant /unexpected or no reading from lambda probe so puts warning light on.

mutley
February 2009

But if your car is a diesel follow this link

http://www.theaa.com/motoring_advice/fuels-and-environment/diesel-particulate-filters.html

Peccavi
February 2009

They screw into the exhaust sysyem. The Lambda sensor monitors unburnt oxygen in the exhaust gas and "talks" to the engine management unit to properly balance the fuel/air mix going into the engine.

They used to put lead in petrol but now they put poisonous chemicals in it - the Lambda sensor helps to make sure the poisons all get burnt up.

Peccavi
February 2009