Good afternoon 

My 06 fabia has had a lambda sensor fault for a little while, brings up the code P0135. Tried a new sensor and it the issue didn't go away, so I took it to my local indy who had an auto electrician out to look at it. He thinks there is a broken wire from where the sensor plugs in back to the ECU, or it could be a fault with the ECU itself. Just curious if anyone else has had this issue before and wouldn't mind shedding some light on what to look out for, maybe what wire could be broken? They said it's reading data but the heater element isn't reading properly. Engine code is BKY.

Edited 14 August, 20241 yr by Kalum0101

I have the same issue with my 2.0, I think vibration has fractured a heater element wire somewhere very inaccessible, it's on the hit list but keeps slipping down the list of priorities since it needs to have the inlet plenum removed for access.

Yeah, it's been on my list for a while, but with it's MOT just round the corner I need to get it sorted or it'll fail. Don't suppose you know which wire is for the heater element?

Power to heaters of both oxygen sensors are the blue/red wires, originating at cabin fuse 9.

Control is via the brown wire for precat sensor, and the brown/white for the post cat sensor. They go to engine ECU pin numbers 5 and 63 respectively.

Amazing thank you. Now I just have to pluck up the courage to strip the car apart to trace the loom. Hoping its not an ECU fault.

Far more likely to be a wire or connection fault.

So I didn't get the time to look at it myself due to it being a busier than average month for me, so I took it back to the garage for them to diagnose it further and they said they think its the ECU and it has now gone off for testing. My skepticism is making me wish that I tested all the wires myself....

 

How often do the ECUs fail on these? I find it hard to believe that a ECU fault could cause just one thing to go wrong.

ECU faults almost never happen.

Wiring faults often happen.

So they've potentially gone down a rabbit hole that they didn't need to, costing me money in the process.

 

Guess I shouldn't be too surprised. My Vectra had a front end rattle that got diagnosed as a suspension issue when it was a missing Brake Pad retention clip...

5 hours ago, Breezy_Pete said:

ECU faults almost never happen.

Wiring faults often happen.

 

Hear-hear!