on March 18, 2011, 4:55 pm, in reply to "Seat Leon 1.4 2001 - MOT Emission Failure + EML Illuminated, codes P0030, P0036 & P0141 #"
According to AD, terminal 3 (heater supply) should be blue/yellow and is batt volts from fuel pump relay via fuse 43. This also supplies HO2S B1 S2. If you only have 2.95v at this wire that may explain DTC's for both sensors? Term 4 should be green/yellow and is the PWM earth for the heater.
because of the change of colours it's a bit confusing but I think the feedback was the yellow wire from the sensor and perhaps it was 450mv not 2.5v as I thought?
HTH's,
Bryan.
PS. Just read that if the heater is not working that will clog the diffusion gap and trash the sensor.
