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Ron Z.
Ron Z., - Chrysler Tech -
Category: Chrysler
Satisfied Customers: 18871
Experience:  18+yrs experience. State Inspector & Chrysler Diagnostics
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PO-456 EVAP EMMISSION CONTROL SYSTEM LEAK ... I have a chrysler pacifica and have replac

Customer Question

PO-456 EVAP EMMISSION CONTROL SYSTEM LEAK ... I have a chrysler pacifica and have replaced the gas cap.
What else can I do or buy toget this light off? Any help would be greatly appreciated!
Submitted: 5 years ago.
Category: Chrysler
Expert:  Ron Z. replied 5 years ago.

Welcome to! My name is DriveFast71(Ron) and I will do my best to answer all of your questions completely and accurately.


The P0456 is "EVAP System Small Leak Detected". This is a very tough one to diagnose. The best method to diagnose this, is to have the EVAP system "smoked". This is where a machine forces smoke through the system, and the "leak" will reveal itself. Prices vary for this service from shop to shop, but it's the most efficient way, as trying to find a "small leak" in the EVAP system can drive you crazy! There are a few common things to check before the smoke test:


  • Leak at Gas Cap
  • Visual and physical inspection
  • Verify Evaporative Emission Leak
  • EVAP Purge Solenoid Operation
  • Evaporative Emission Leak Detection


Make sure the fuel cap you replaced meets Chrysler OEM specs. For example- those "universal" or "discount" caps will not meet specs, and will not seal the system. The Purge Solenoid is also a fairly high rate fail item.