We have a 1999 Dodge Dakota 4x4 king cab with about 60k on it. We have had the engine light on for a year that we can clear with the code reader. The code suggests emissions leak. The code clearing lasts a few days then comes back. One mechanic said replace the charcoal cannister. Another said he'd never sold one and didn't know of any ever being replaced. We can spend $100 and replace the cannister and have the code possibly come back or do a smoke test and spend a little less. Any ideas?

 

Which code specifically are you getting?

If it's the PO456 Small Evap Leak try this:

Take your gas cap off, grab a pen or something you can poke the little check valve with, and give it a furious working in/out to see if you can't free it up if it's binding and causing a small leak. I kept getting the code and that's what I did, seems to have fixed it. Most dealerships will sell you a new gas cap. I don't think you need to buy anything.

 

Yes that's the code and we did all the gas cap tricks and even replaced it. A mechanic told us we will blow the vacuum pump eventually and my husband says he hears it going on constantly so if we don't fix the leak.....goodbye pump. Does the fact that after the code is cleared it takes about 50 miles to come on again, have any significance? We didn't try the valve trick tho, we will try that asap. Thanks!

 

Found out it's a large emissions leak not a small one

 

go to another mechanic. those charcoal cannisters are supposed to be good for the life of the vehicle, something like 20 years. im mostly a ford guy but they should be the same: theres a canister purge valve along that vacuum line that is much more likely to have failed. in your manual there should be a procedure for doing a resistance test on the valve, its not 100% accurate but sometimes it shows a failed part

 

Check ALL the vacumn hoses and connections. Mine was caused by a dried out and cracked U shaped hose on the charcoal canister itself. A piece of old hose I had laying around-easy fix.