Poor signal from crank sensor.. help!

[JonnyClio]

The other day I had to pick my girlfriend up from town late at night and my car started fine, but I realised I then had to move my brothers car out the way to get out and when I got back in my car it wouldn't start. I'm awful with the terminology but the engine basically wasn't starting when I turned the key... after trying to jump start it and then dragging my parents out of bed it started on it's own...

Then at college yesterday it did the same thing again... My girlfriend started my engine claiming she was going to reverse it out and drive it but I turned the engine off and then 10 minutes later it wouldn't start, and in the end I had to get the AA to come out (luckily im a member)... He fixed it by cleaning some magnets somewhere near the engine haha... and on the report sheet he gave me it said I had a "poor signal from crank sensor".

Basically looking for some advice:

1. Will this be a permanent fix, or how long term will it be? I asked him and he said it may have sorted it or I may need a new crank sensor or something along those lines.

2. Could someone crashing into the back of me have caused this? Sounds like a stupid question but it never did it before my crash...

3. Has this happened to anyone else? Is it self-fixable?

Cheers guys

 

[JackJack]

1. Time alone will tell if it was just clutch dust contaminating the sensor or an actual fault with the sensor itself. If it happens again get a new sensor.
2. No it's a coincidence.
3. Quite common easy to replace the sensor.