djhall195

a 2007 equinox wont go in ready mode for evap and egr systems after 1 mo and 2k miles of driving. dealer replaced cannister for a p0442 code and said just keep driving it. They dont have a clue whats wrong. Anybody have an idea?

Chevrolet Customer Service

<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:PunctuationKerning/> <w:ValidateAgainstSchemas/> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <wontGrowAutofit/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--><!--[if gte mso 9]><xml> <w:LatentStyles DefLockedState="false" LatentStyleCount="156"> </w:LatentStyles> </xml><![endif]--><!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} </style> <![endif]--> Would you please PM me with a description of the problem(s) that is occurring and your VIN, so I may see if any additional information is available?

Louis
GM Customer Service

tech2

Some background information would be helpful. Do you need to pass a state emission test? Story from the begining?

if your saying the ecm won't run the I/M monitors. Each monitor has conditons that must be met before it is run. Maybe your drive cycle isn't meeting the requirements or a fault is still present?

For example; the evap monitor won't run if the fuel tank is over 3/4 or under 1/4 full. evap monitor tests p0446, P0455, and P0496 must run and pass before the p0442 diagnostic will run.

The egr monitor won't run if a dtc in the map sensor is present. After the problem is fixed and the dtc cleared with a scan tool; the egr monitor will run 18 flow tests to confirm the system is functioning.

So... check for any other dtc and post the codes if any.

djhall195

Thanks for answering. This started wiith a state insp that failed due to mil on, p0442 code. Dealer replaced cracked cannister and informed my friend to drive vehicle for a couple days to get in ready mode and then get it inspected. it failed due to not ready state for evap and egr. she was informed by dealer to keep driving it . 2 wks later, still failed I found a drive cycle posted jan 2008 and loaned them my scan tool. after trying sat and sun still not ready with no pending or curret dtc's. Chev dealer said they can reflash pcm, try drive cycle then check for pending codes?

angelostl@sbcglobal.net

I've seen this before and it was a small evap leak. You may not see any failures when viewing Mode 6 for EVAP either, this has happened using generic scan equipment such as AUto Enginuity. Do some real details evap leak testing or leave smoke on for an extended period after purging evap system to fill it with smoke. Be in a position where you can monitor any smoke rolling off the top of the tank after an extended smoke test. Make sure there is no wind or air movement to blow away slight smoke leakage. If you have a CO2 evap tester with color-changing foam that would be beneficial. Saw a hairline crack in the top of a fuel pump module do this. Get vehicle history to see if there was any work done in the area of the tank, evap system, etc.

tech2

are you suggesting the use of aftermarket scan tools will show the monitors incomplete? please explain.




what is the purpose of testing anything? the monitor hasn't run and failed. the system could be fixed for all anyone knows. He just wants the monitor to run to confirm or deny this.


to the op. at this time, what monitors have yet to run to completion.

angelostl@sbcglobal.net

The tech had only this aftermarket scanner to use.
What I am saying is I've had this exact issue on three of the subject vehicles and the problem was an evap leak which did not set a code. The evap monitor had failures midstream and did not complete and this also suspended the EGR monitor.