Wow, even more excellent footwork and disappointing to hear that they cannot help. Often when a company stops manufacturing a part there is a supersession or alternative part available, although in this case it sounds as if there isn't. Whilst you were successful with the seal I suspect finding an alternative sensor from scratch would be much more complicated and expensive.
On a brighter note, did Tyco say who else or where else they shipped that sensor to, or was is solely to Valeo ? Obviously if it was used in different applications/makes/models then the availability of old stock elsewhere could be easier. On that theme, while Valeo were unhelpful with the seal do they have a stash of sensors that they're sitting on ?.
Although there are many stories of CSC's failing presumably through age and wear, is failure due to the sensor a common issue, or is it part that actually lives a very long time, and shouldn't be a worry ?
By the way congrats on votre anglais, I live in 65220 and still can't order a beer without 2 or 3 attempts

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