1 incomplete Readiness Monitor - Evaporative System

[treehan77]

DashCommand is reporting that i have 1 incomplete Readiness Monitor on my 05 Yukon 4.8L. It shows "Evaporative System" as the one not ready. What does this mean, and how to fix it or troubleshoot it ? There is now Check Engine light or codes etc other than this. I haven't had the battery out lately or anything...

 

[SLCHOE]

DashCommand is reporting that i have 1 incomplete Readiness Monitor on my 05 Yukon 4.8L. It shows "Evaporative System" as the one not ready. What does this mean, and how to fix it or troubleshoot it ? There is now Check Engine light or codes etc other than this. I haven't had the battery out lately or anything...

What it means is it has not met it's criteria in order to run the monitor in order to give a pass/fail flag. It's simply not ready until then.

Evap systems usually need 1/4-3/4 full tank of gas before it will run. No less than a 1/4 tank or it wont run. Start it cold and drive it.

It may have a code pending that goes away as you drive it keeping the monitor from running... doesn't have to be an EVAP code either. A pending code will restrict monitors from running. The code may go away and never set the CEL.

First thing i would do is get a code reader and keep it in the truck. Check for pending codes every once in a while.

Or get a cheap Autel code-reader that has I/M readiness monitoring if all you are trying to do is pass I/M. When the reader clears it as ready, head straight for the I/M station and fix the problem afterwards.

This will most likely not be an easy fix.

 

[treehan77]

What it means is it has not met it's criteria in order to run the monitor in order to give a pass/fail flag. It's simply not ready until then.

Evap systems usually need 1/4-3/4 full tank of gas before it will run. No less than a 1/4 tank or it wont run. Start it cold and drive it.

It may have a code pending that goes away as you drive it keeping the monitor from running... doesn't have to be an EVAP code either. A pending code will restrict monitors from running. The code may go away and never set the CEL.

First thing i would do is get a code reader and keep it in the truck. Check for pending codes every once in a while.

Or get a cheap Autel code-reader that has I/M readiness monitoring if all you are trying to do is pass I/M. When the reader clears it as ready, head straight for the I/M station and fix the problem afterwards.

This will most likely not be an easy fix.

Thanks! I have code reader, it shows 0 stored codes found, 0 pending codes found and 0 permanent codes found. I've checked it a few times now, and it always say Not Ready for Evap. I haven't yet ran a full tank of gas through it though, perhaps it'll take a while to "be ready"? Can you elaborate as to why this won't be an easy fix? I don't need to pass any emissions tests. As long as i don't get any codes thrown, should i even worry about it?

 

[SLCHOE]

Thanks! I have code reader, it shows 0 stored codes found, 0 pending codes found and 0 permanent codes found. I've checked it a few times now, and it always say Not Ready for Evap. I haven't yet ran a full tank of gas through it though, perhaps it'll take a while to "be ready"? Can you elaborate as to why this won't be an easy fix? I don't need to pass any emissions tests. As long as i don't get any codes thrown, should i even worry about it?

If you have never had any codes thrown and your evap is not ready, no codes stored, first thing i would do is check your gas cap gasket. Pull off your gas cap and look at the rubber sealing ring. If it looks questionable, get a new one.

Also, never fill your tank with the engine idling.

Always make sure the cap click a few times when tightening.


The reason i said it wouldn't be an easy fix is beacase there is no obvios cause of the problem. No codes. No obvious symptoms.

 

[JKmotorsports]

A "not ready" monitor doesn't mean anything is wrong. All it means is the specific procedures for the test monitor to pass haven't been met. Some monitors require specific actions for the test to pass, i.e. , certain speeds for a specific amount of time, specific ambient temps, coolant temps within a certain range, fuel level range, etc. Unless there is a dtc, an incomplete monitor isn't anything to worry about.

 

[SLCHOE]

A "not ready" monitor doesn't mean anything is wrong. All it means is the specific procedures for the test monitor to pass haven't been met. Some monitors require specific actions for the test to pass, i.e. , certain speeds for a specific amount of time, specific ambient temps, coolant temps within a certain range, fuel level range, etc. Unless there is a dtc, an incomplete monitor isn't anything to worry about.

While you are correct on everything you said..


In most states: 1996-2000 means you can have 2 monitors "not ready" and still be able to run the emissions test.

2001-Presesnt you can have 1 not ready and still run the emissions test.

Keep in mind. This doesn't mean you "FAIL" the emissions test if your vehicle is determined "NOT READY". It simply means your vehicle was "NOT READY" to test in a Pass/Fail scenario. The on-board monitors determine that in certain systems of the vehicle's emissions system.

CEL/MIL ON: Automatic FAIL.

Different brand vehicles require different drive criterea/cycles to reset each monitor. As a rule of thumb, 50 miles of mixed highway and city driving as well as letting it sit overnight and driving it again for 15 more miles in the same conditions will let most monitors run. EVAP monitor will only run with nmore than 1/4 tank fuel.

 

[treehan77]

Just scanned the Yukon again, it now shows no incomplete Readiness monitors. I read up about "GM drive cycles" and some of the things that needed to be done were things i would probably never do to get it "ready."
-Have defroster on for a while
-Coast from about 60 mph till stopped.

Like i said, i did these things a few times and driveit about 50 more miles and the EVAP monitor now reports that it is ready. Cool. Ridiculous but cool, at least i know i don't have any issue.