1996 850 Knock sensor upgrade/revision?

[Jazzop]

I have seen in various places the mention of a Volvo retrofit knock sensor assembly. Apparently the original design had some issues and Volvo recommended retrofitting all cars equipped with the original parts.

1. What is the backstory on this problem? I'm curious about why they made the change.

2. How do I identify the old vs. new knock sensors?

Thanks.

[dosbricks]

It was not the knock sensors themselves per say, I believe, but the wiring which was subject to fraying. So the retrofit kit gathered the wiring into a harness and included a mounting bracket to keep it tucked in place. I saw the kit before it was installed on my wagon. If you have the latter, your car has probably been updated.

[Jazzop]

When I cleaned the breather system last year I noticed my knock sensor wires were completely exposed (the loom had crumbled away), so I rewrapped them with silicone tape along with many other areas of my engine wiring loom. At the time I was unaware of the redesigned part from Volvo.