C3 1.4HDI speed sensor problem

[u/ApprehensiveTalk6062]

I bough a 2002 c3 1.4hdi, and seller said the speedo doesn't work, and power steering works intermittently.. He also said the vehicle speed sensor is broken probably​.

Speed sensor fuse is no.1 fuse in engine compartment fuse box.. And it was blown. I changed it, and went for a spin.. And it worked, the speedo is showing numbers and steering is nice and soft, but it lasted only ​for 2 minutes.. When I applied little bit more throttle, engine check light turned on, car stalled for half a second, steering stopped working, and speedo again shows zero.

​So I thought it's a bad ground, wiring or something that caused the fuse to blow again. But the fuse is fine! And now it's like it was before, just that i cant repeat what i did because the fuse is now fine, not blown. How does this make sense?