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Hi all,

i have this fault code showing and im pretty sure it's just messed up my emissions test at an MOT

17524 - oxygen (lambda) sensor heating B1 S1 open circuit P1570 -35-00

where is the pre cat lambda sensor (assume is near the exhaust manifold)? is it most likely to be the actual sensor or the wiring?

many thanks,

Dan

It's just by the heat shield on the front of the engine. Check the wiring on the plug as the commonly breaks causing a sensor fault.

I'm a bit of a spaz with a multimeter. Can someone tell me how to test wether or not it's the sensor or the wiring. I know I need to test the resistance of the sensor and presumably the voltage coming to it.

Can I have a idiots guide

Perform a visual check for broken wires. They'll be obviously broken if that's the case

Thanks Alex

Really appreciate your advice, I'm determined to get her back on the road!!

I think its the wiring thats at fault. the green wire going to point 3 on the connector has been severely damaged and the green one going to point 4 on the connector has a nick in the insulation.

what do these 2 wires carry? More importantly how do you fix damaged wire, never done it before

Also how do i check that lambda sensor is working, as it could be both parties at fault??

That's badly damaged

Both wires will need replacing with VW repair wires available from the dealer

There is another thread that details the part numbers you need if you search for it.

The Sensor is likely ok. Once the wiring is fixed the fault should clear.

I snipped out the damaged section and crimped in a butt joint and taped up the exposed wire on the other cable. I cleared the fault an so far it's not come back!! Now I should be ok on emissions!!!

emissions are spot on now. passed the MOT now to get a VIC done