just serviced my wife's 54 plate Fabia 1.2 12v, passed MOT last week with no problems. Told by the mechanic the engine numbers were excellent ( CO2, CO, NOX etc ) and the lambda value on their machine showed 1.015

Whilst setting the service numbers back ( instruments, adaption then set 02 to value of 0, sets all miles, time etc back to post service numbers )

Checked for fault codes. Engine came back with 17511 oxygen lambda sensor heating B1 S1 performance too low P1103 - 35-10 - - - Intermittant

The yellow engine management light on the dash is NOT on and has never come on.

Do I need to investigate, or just clear the fault and probably never see it again ???

Car is running fine, idling is steady, acceleration is smooth, mpg averaging 47mpg

Thanks in advance for any useful advice

Langtone

Clear the code and rescan after a while. It's the first probe that is showing a problem, but it is the probe closest to the hot parts of the engine, so it should still get up to temperature. A probe heater fault will usually bring the light on and emissions will be affected during warm up, as the MOT is carried out at normal operating temperatures the result shouldn't be affected.