Lambda fault after pre-cat removal

[viertel55]

Got a problem folks, can anyone help.

After pre-cat honeycomb removal job car ran fine but engine error light came on after a few miles. This was a year ago. For MOT last year got my friendly garage to reset system for light to stay out  just long enough to pass.
Thought that we better get it sorted at the service this week (because fault light on all the time could mask any other fault). Same garage put in a new probe today. After only 3 miles fault light came on again! Garage tester plugged in said No1 Lambda sensor faulty. Garage reckon extra heat on sensor is causing failure.

Thoughts please anyone?!!

Hans Viertel

Roche,
Cornwall

[spit]

"Extra heat on the sensor" is an enthusiastic theory   s:D s:D  . I reckon you can park that one as v unlikely unless your engine is seriously ill and throwing up other codes too!

An independent garage may have fitted an NTK OEM-equivalent or suchlike from their local parts supplier. If they picked the wrong 'suchlike' you might well have nothing more than a heater circuit code..... but it needs to be addressed.

Did you get the precise error code from the garage? Many non-standard sensors have a lower resistance heater circuit than stock which the 2's ECU will throw up as a fault in next to no time. This would seem to fit with your symptoms. You need to ensure that the garage used a Denso sensor (currenly less than £50 from sparkplugs.co.uk). If they didn't, they should put it right. If they fitted a sensor that failed within a few minutes, they should be offering to do this anyway   s:? :? s:?  

As for your original problem, its not unusal for tired sensors to go faulty after being removed, replaced or jostled during something like precat removal.... but its usually the brittle heater circuit that fails rather than the sensor's sensoring. Again, did you get the error code read first time round?

Irrespective, its not the best thing to tootle round with an engine light on, as you rightly recognise   s:wink: :wink: s:wink:  If your car is a UK model, code readers are cheap as chips and can keep you informed and/or clear your engine light, depending on how involved you want to get. A quick search on the forum will throw up some models used/recommended by members.