EVAP not ready. Could use a helping hand

2004 Silverado. Chasing and fixing evap code gremlins. Decided to kill the CEL by setting evap parameters to not reported. CEL went away, but evap system would never report ready status, always incomplete. Truck runs fine, just needed to pass state inspection to get a sticker. I then went and changed the parameters 2 different times to get it to report, and or throw a code. It still does not throw a code, but evap never ready .If you have a moment, would someone mind looking at my files and point me in the right direction.

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The diagnostics for a readiness monitor must be able to run AND PASS. With the codes disabled it will never show anything other than 'not ready' or incomplete because disabling the codes tells it to not run the tests. Disabling the codes does not change an I/M item to 'not supported' like it would be on a vehicle that was built without that system, like the HD trucks without rear O2 monitoring.

edit: oh, right, I answered this in your previous post. I guess you didn't like my answer and decided to spin the wheel and see if someone else would give you an answer you liked better?

I can't look at your tune file but if you unchecked the SES Enable box try checking it back for the evap codes you set to NER.

Quote:

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Originally Posted by blindsquirrel

The diagnostics for a readiness monitor must be able to run AND PASS. With the codes disabled it will never show anything other than 'not ready' or incomplete because disabling the codes tells it to not run the tests. Disabling the codes does not change an I/M item to 'not supported' like it would be on a vehicle that was built without that system, like the HD trucks without rear O2 monitoring.

edit: oh, right, I answered this in your previous post. I guess you didn't like my answer and decided to spin the wheel and see if someone else would give you an answer you liked better?

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I thought this sounded familiar

blindsquirrel...I apologize, it looked like my post did not post, and I couldnt find it, so I posted again. My bad. ..I promise, I'm not second guessing your advice. I will check it out. I re-enabled the codes, but now it still doesnt throw codes, nor will it go into ready status.

Some vehicles can take a lot of driving to get the ready status to set.

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Inspection/Maintenance Evaporative Emission System Set

Description
The purpose of this procedure is to satisfy the enable criteria necessary to execute inspection/maintenance (I/M) readiness diagnostics for the Evaporative Emission (EVAP) System. The procedure may be used to set the EVAP I/M System Status display on the scan tool to YES. The EVAP I/M System Status display indicates whether or not the control module has completed the readiness diagnostics. The readiness diagnostics complete when all DTCs comprising the diagnostics run and pass, or any DTC comprising the diagnostics illuminates the malfunction indicator lamp (MIL). If the diagnostics pass during one drive cycle, seventeen hours must elapse, regardless of whether the vehicle is driven or not. Then, the diagnostics will run again during the next drive cycle in which the conditions for running are met. Once the diagnostics have passed during the third drive cycle, the EVAP I/M System Status display will be updated to YES. A failed or aborted diagnostic will require the vehicle to cool down in order to meet the enable criteria for another drive cycle. Therefore, performing a visual inspection prior to running the EVAP test may prevent having to repeat the drive cycle.

Conditions for Running
? At least 17 hours have elapsed since the last drive cycle met the Conditions for Running.
? The difference between the startup engine coolant temperature (ECT) and the startup intake air temperature (IAT) is less than 8?C (14.4?F).
? The barometric pressure (BARO) is more than 74 kPa.
? The startup ECT is between 4-30?C (39-86?F).
? The startup IAT is between 4-30?C (39-86?F).
? The fuel level is between 15-85 percent.
? The battery voltage is between 10-18 volts.
? The fuel level does not increase more than 9 percent during this drive cycle.
? The engine run time is at least 10 minutes.
? The vehicle has been driven at least 5 km (3.15 miles) this drive cycle.
? The estimated ambient temperature at the end of this drive cycle is between 2-32?C (36-89?F).
? The shutdown ECT is at least 70?C (158?F).
? The ignition is turned OFF for at least 1 hour after this drive cycle.

Diagnostic Aids
Extreme high or low ambient temperatures may prevent the EVAP System Tests from initiating. A loose fuel cap may cause a test to abort or fail and prevent the I/M System Status from updating. A failed or aborted diagnostic will require the vehicle to cool down in order to meet the enable criteria for another drive cycle.

If there is an impending failure, the system may require more time to run the diagnostic than was allotted in the set procedure. If the diagnostic does not run after numerous attempts and no DTC is set, review the appropriate scan tool data list and the service information. This will give an indication of why the test does not complete. Some diagnostics may abort due to changes in the conditions while the test is running. For example, changes in engine load, such as a cooling fan or an A/C compressor clutch turning ON, may cause the diagnostic to abort.

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Just a teaser, there's more in the service manual. Including TSBs. Can't work on these things without resources.

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