22 replies to this topic

[Bakazan]

Thanks both, I'll check the resistance/continuity across the white wires at the weekend.

 

I had a look at the wires and there was no obvious damage despite the nearside boot drain dumping water onto that cable.

[Mangham54]

I found that the sensor wire had a break by using a multimeter to check for resistance. There was no resistance in the sensor so we felt the cable and found a 'lump'. Stripping it back clearly showed the break, so crimped and waterproofed it and hey presto resistance and no eml

[DarkAge]

The downstream post cat O2 sensor should not be switching.

 

P0140 can also be a leak in the exhaust precat. I just had this on my polo a month back, was a crack in the flexi pipe.

 

More info here:

O2 Sensors

A/F Sensors (wideband O2 sensors)