As long as your existing harness isn't totally screwed - you can remanufacture it yourself. Wire is cheap and easy to source, and the pins & wire seals are SUMITOMO MT Series 090 pins. I get my stuff from
www.polevolt.co.uk
Connector housings are still available from Toyota, but usually your existing one is salvageable, just de-pin it, scrub it with a little gasoline on a toothbrush and fresh wire, wire seals & pins and they're good as new. The insulation on the wiring just peels off - and can be got from eBay.
Just replace the wire from ECU connector to the sensor connector in one go - no splicing unless it's absolutely necessary.