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Q: Check engine light came on on 1999 Volvo V70 XC

Hello, I have a 1999 V70 XC AWD.
The check engine light came on and the volvo dealership in Brooklyn told me to replace the Oxygen sensors, front and rear. After a few miles the light went on again. Volvo dealership replaced the engine wiring harness to sensors, but after a few miles check engine light came on again. Now the volvo dealership tells me that the main engine harness need replacement. Does any one know more about this issue?
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And what will be the next part after the main harness? The Engine Control Module?
It's hard to tell without seeing it. There is an adapter cable for both O2 sensors to eliminate false O2 DTCs, but looks like they already installed that.
I have seen some S-V70 where the rear cam seal was leaking oil to the O2 sensors main connections- causing problems. I'd make sure it's not the case.
Do you have the exact DTCs??


There was an issue with the wiring harness to the O2 sensors, but there are wiring adapters that attach in line between the sensors and the wiring harness that is supposed to address this.
Unfortunately the diagnosis here seems to be questionable, but without actually knowing why they are recommending the sensors and now the wiring harness it's hard to know.
I would ask for a second opinion from another technician in the shop, preferably the shop foreman. And ask that they guarantee the repairs they recommend, or they should pay for them, not you.
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