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Mike V.
Mike V., Auto Mechanic
Category: Dodge
Satisfied Customers: 25180
Experience:  25 years automotive expierience, Nissan factory trained, Subaru factory trained.
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I have a 1999 Dodge Caravan with a trouble code P0455 (Evaporative

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I have a 1999 Dodge Caravan with a trouble code P0455 (Evaporative Emission control System Leak [gross leak]). I repaired a vaccum leak and replaced the pvc valve as well as the hose (cracked
Greetings and welcome to JA! I will do my very best to assist you with your problem.
OK, this code is for the evap system and not the engine. This is why the code came back on you.
The most common cause for this code is either a bad leak detection pump, faulty fuel cap or fuel filler tube. The LDP is located under the van in the area of the rack and pinion. If the tubes have come off or if the pump has stopped pumping it will cause a large(gross) evap leak in the system
Customer: replied 6 years ago.
How do I test the pump for propper operation?
Here is the procedure! Hope it helps!
1. Remove all of the rubber evaporative hoses to check for deterioration from the inside out.

2. Check the purge solenoid. It should block vacuum when de-energized.

3. To check the Leak Detection Pump (LDP), connect a test light to the Yellow/Black (YL/BK) wire. The test light should light with the Key On Engine Off (KOEO).

4. Start the engine and ground the White/Dark Green (WT/DG) wire with a jumper wire. The test light should go out.

5. Remove the ground and the test light should light up again.

6. Remove the large outlet hose from the LDP that goes to the canister and block the nipple on the LDP.

7. Ground the White/Dark Green wire and the test light should go out.

8. Remove the ground and the test light should stay out for at least 10 seconds if the LDP is good.

9. If the test light lights up within 10 seconds after the ground is removed from the WT/DG wire, the LDP is leaking.
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