I have an 02 Grand Caravan that just started the 0456 code. The gas cap looks fine and I found not obvious hose cracks. The shop did a smoke test and found nothing. The only part they did not test was the leak detection pump. The part and labor was about $350. I thought I'd try one from the junk yard first. I've been told the LDP is located below the breather box and a manual for a 2003 says it's underneath the vehicle about midway back. Does anyone know exactly where the LDP is located on an 02?

Thanks

 

It is inthe Middle of the car, roughly under Driver's seat, by the Rack and Pinion assy.
The pump should be $145 brand new. It should take u no longer than 15 minute to change it.
If you smoke test everything and found no leak, the problem will be the LDP, almost always the case for me.