had large and small leak code. took care of that problem. replaced bad hose to canister. replaced canister as it looked damaged got new code a week later 1494. replaced leak detection pump and vent solenoid . problem still persists

 

Read here.

Are you sure you didn't get a bad new part, right out of the box?

 

yea I got part from local part store. got it replaced. cleared the code and after second run of truck,it pops same code. I checked all vac hoses going to intake and going to canister. I changed pvc valve and hose because the hose was brittle and starting to crack.I did soapy spray water all around vac hoses and nothing turned up

 

Soapy water isn't going to show you anything on a vacuum leak..... Need to smoke test the system. (pressurize the system with colored smoke, so you can see where the leaks are.)

 

this is on a 01 ram 1500 5.2 liter 2wd with 140,000. does any one know if there is constant power to that leak detection pump.Also I did replace the main pcm when I first got the truck year and half ago. the idle would never go down and had it tested and it was bad. it has been perfect ever since

 

that I will, but it is strange when ther was a leak it was popping a code of large leak and small leak. no more codes like that just the 1494 code leak detection pump switch.is there suppose to be constant voltage at switch when turned on

 

I don't think so. Grab the service manual for your truck from here. Wiring diagrams are in section 8W.

 

The code is more likely caused by a crack in the rubber elbows that connect the vacuum lines to the canister and leak detection pump... Check all hoses and connectors before replacing any other parts and the hose connectors are easier and cheaper to replace.. the rubber connectors are known for dry rotting and cracking there by losing vacuum and triggering the code.