Hi Brian,

There may well be something in your method of observing the direction of flow of the pump current but it is not something I have practiced or felt the need to do. Having said that I might just do a bit of research next chance I get.

Hi Pete,

I have to agree with Aiden! With any emissions problem it is most important that ALL the lambda sensor is working correctly as the internal heat from the heater will get the Sensor Up to temp Quicker and keep it there. Where as relyiing on external heat from the exhaust stream is not consistant. There are guidelines for Testers to follow when carrying out an emissions test, usually instructions from the gas analyser, and if it fails when these guide lines are followed then its a fail. irespective of whether it would have passed if they had cruised it for another ten mins and then carried out the test.

Modern O2 sensors heat up very quickly and I have observed engines running in closed loop within minutes of cold starting, thats how good they are.

Do not allow a tight ***ed Customer to dictate to you, If he wants a pass and he wants you to achieve that it needs the heater circuit faults sorting.

Just my honest opinion.

Mike