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99ML320
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Discussion Starter #1
Hi All, need help with OBDII code P0442. I search the forum but found little information. My truck is a 99ML320 with 82K miles on it. I was monitoring the P0172 & P0173 codes after the CEL went off by itself and reset the code after about 100 miles of driving without the CEL comes back on. I believe the P0172 & P0173 codes were due to the gas cap as the CEL came on after I re-fuel the truck. And now there is a P0442 code but without the CEL light on. Would appreciated if anyone could help.

Jay.
 

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Registered
99ML320
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64 Posts
Discussion Starter #3
thanks for the response. I some more info from another forum stating the following:

"Check Engine Light comes on when the
two gates (purge valve and shut off valve) are sealed off, and the system is
sensing a small leak. A "healing code" is then stored (P0442?); it is
called a healing code because once the leak is detected and the code is
stored, the system will search for the leak again. When it does not locate
the leak again, the Check Engine Light will go out."

The funny thing is that the CEL is NOT on but there is a code. I'm trying to reset the code but wasn't able to as I did with the previous codes. I hope that it will go away in several driving cycles.

Jay
 
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