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Richard, Jaguar Technician
Category: Jaguar
Satisfied Customers: 15522
Experience:  12 years at a Ford/Lincoln Mercury and Jaguar dealer as technician and shop foreman.
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My codes are P0442 Multiple Misfire and PO456 Very Small Evap.

Resolved Question:

My codes are P0442 Multiple Misfire and PO456 Very Small Evap. Fuel cap is tight. Codes were erased, but reappeared after ~150miles. Would appreciate your suggestions as to where to look. This is a 2005 Jaguar S-type sedan. Many thanks. Phil
Submitted: 7 years ago via OnlineAutoRepair.
Category: Jaguar
Expert:  Richard replied 7 years ago.
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Richard :

Hello and welcome to

Richard :

The code P0442 is a small evap leak and P0456 is a very small evap leak. If you already replace the fuel cap then it is vey possible you have a leak in the system or the canister valve is faulty. The problem is that you will need some special equipment to test the evap system. You will need a scan tool and a smoke/leak detection machine which pressurizes the system.


You say that both codes, P0442 and P0456, are evap leaks (one small, and the other very small). The dealer originally said that P0442 is multiple misfire. Who is right?

Richard :

P0442 is not a multiple missfire. I can tell you that 100%.

Expert:  Richard replied 7 years ago.
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Customer: replied 7 years ago.
Richard, I am puzzled because I am assuming the dealer is using the authorized Jaguar code manual, which states that P0442 is multiple missfire (He is an authorized Jaguar dealer, the leading dealer in our region). I need to confirm this with him when he opens on Monday August 16. I will then get back to you.
Expert:  Richard replied 7 years ago.

I understand your confusion but I guarantee you that P0442 is an evaporative emissions leak. Click on the link.



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