Failed Emissions Test - OBDII Failed Communications

[mp911]

2001 C2 with 95K miles here in Illinois.  Brought it in for the required emissions test to the same facility as a few times in the past.  Technican had hard time finding the OBD port (seemed inexperienced) and then spent a lot of time messing around with the connector to get the machine to read my car.  Finally was told the car failed due to OBDII failure.  "Take it to a repair shop and come back."

 

Came home and grabbed my hand held scanner, plugged it in, scanned - no problem.  No codes, MIL off, all sensors ready.  Then plugged in my duramteric and spent the next 15 minutes playing with it, trending date, checking for codes, looking at all the modules.  No problems except I have a code on the airbag indicating low voltage but the airbag light is off (subject for another post).

 

Unless someone has run into this before I am thinking of heading to a different test station and see what happens.  You only get three chances before having to jump through a pile of hoops though.

[Loren]

You will need Durametric or PIWIS to see pending codes. In most states a pending code is cause for smog test failure.

[Ahsai]

You said "Finally was told the car failed due to OBDII failure". My guess is the DME times out when waiting for the tech to connect. Maybe try another smog station?

[mp911]

My apologies, the reason given for the car not passing was OBDII COMMUNICATION failure.  They could not get their machine to read the OBD on my car, something like a bad connection.  When I got home and used my duramteric, it was fine, no codes or problems at all noted with the emissions systems.

[Ahsai]

My apologies, the reason given for the car not passing was OBDII COMMUNICATION failure.  They could not get their machine to read the OBD on my car, something like a bad connection.  When I got home and used my duramteric, it was fine, no codes or problems at all noted with the emissions systems.

Yes, I understand. That could be because he left the key in the crank position for too long that power/communication to the OBDII port was cut.

Also possible he didn't make a good physical connection at the port so some pins are not electrically connected.

 

If you can connect with your scanner, I can only think of the above reasons that why the shop's scanner failed to communicate with the DME.

[Silver_TT]

Maybe not very likely but another possible reason you could connect but the emissions could not would be if you are running an after-market flash or any other kind of "defeat".  I experienced this where Durametric/PIWIS said "pass" for all readiness states and everything looked perfect using them to check for emissions..... but the state's 3rd party software was smart enough to know that the flash wasn't stock and gave an error similar to what you are seeing. 

[binger]

I agree with Ahsai the tech waited too long and the CAN / k-line bus went to sleep. We always put the hazards flashers on so the bus will stay awake.

Edited May 22, 2015 by binger

[JFP in PA]

I agree with Ahsai the tech waited too long and the CAN / k-line bus went to sleep. We always put the hazards flashers on so the bus will stay awake.

 

It is sometimes amazing how few "professionals" do not know that these systems can go to sleep on you.

[mp911]

UPDATE - went to a different smog testing station - this time with a Tech who took good care and seemed to know what he was doing - and passed with no problems.  Thanks for the help.

[ttocs]

I just did the Illinois Air Team emissions test today and experienced the same issue.

 

I hate being in "the little room" they put us in while testing the car. I noticed the tech shaking his head and making multiple connection attempts to the OBD port. Upon the instance of the first supervisor coming over to override the system I stuck my head out to be party to the issue. Their system wasn't "talking" to my car. I even told them to completely remove the key before another attempt but they weren't going to listen to me.

 

A second, more experienced supervisor came over and assisted in making a third attempt for success. He told me that he's never seen this before on a Porsche, just on Jettas and the like. He said I was lucky because upon three connection failures the system results with an automatic Fail. In my case the system did a "fallback" and my test Passed. So I'm good for a couple years.

 

Now, after reading above about the four way flasher trick I'll be ready for next time.

 

Thank you to the OP and responders for the valuable info. I only wish that I had the foresight to have read this prior to entering the test bay.

 

edit: I wasn't clear about the "fallback". It's the "fallback" that the second supervisor said he's never seen applied to testing on a Porsche before.

Edited August 25, 2016 by ttocs