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Was recently working on a 2012 200 2.4l with a small evap leak. Determined it to be a faulty leak detection pump. However, there's not much to actually 'fail' with this design. If anything, it's just very sensitive to any dust contamination so just wanted to share my testing method. Only specialty tool required is a balloon.

Attach the balloon to the smaller vent port.
Hold the LDP in the same orientation as it would be mounted in the vehicle.
Blow through the canister side port, filling the balloon, and release pressure slowly.
Keep it steady and balloon should hold shape for < 1 min. If it sags, wash it out with water and/or compressed air and retest.
* If you use water be sure to dry it out thoroughly. Electrical connector is just for a contact switch but don't want to introduce corrosion to the contacts.
Don't use any harsh solvents. WD-40 may be OK but anything else is likely to warp the diaphragms.

I did pick up a new one just in case but after cleaning it worked better than the new one. Just goes to show BWD truly is Broke When Delivered.
This design is common to many 2010+ Dodge/Chrysler vehicles so testing method will apply to those as well.



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2016 Chrysler 200 S, 1998 Sebring JX
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The Leak Detection Pump (LDP) is an old term. Since around 2003, Chrysler has used a Natural Vacuum Leak Detector (NVLD).

The LDP used an active pump to create a slight pressure in the tank, charcoal canister and plumbing, then watch a switch change as it held pressure.
The NVLD is a passive system that uses the expansion and contraction of the air in the evaporative system during temperature change. It too uses a switch that has to change state (on/off) to test the sealing integrity of the evaporative system.

Many vehicles have a vacuum line diagram on a label under the hood showing the hose routing and components. It should show the location of the NVLD.
The system is sensitive enough to detect a pinhole leak of 0.010" (0.25mm). Gas caps are the easiest to check. As vehicles get older, some rubber hoses and o-rings can dry rot or deteriorate.

I would be leery of spraying anything into the NVLD, except maybe gentle compressed air for cleaning. It is sometimes called a switch or detector.

I do like the test method using a balloon. Our shop tester uses low pressure air with a flow gauge to indicate a sealed system or not. We can introduce cooled smoke with an added UV tracer to see where it is actually leaking from.
 
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