2007 Chevy Cobalt - did not pass emissions - got 'Unavailable: did not communicate' for the OBD Readiness Monitors status.


Asked by Mar 29, 2015 at 11:51 PM about the 2007 Chevrolet Cobalt LS

Question type: Maintenance & Repair

2007 Chevy Cobalt - did not pass emissions - need gas cap (no prob getting that) but also got 'Unavailable: did not communicate' for the OBD Readiness Monitors status. All fuses in car under the fuse panel are good. Where should I look from here?

17 Answers


How long between clearing the computer after the gas cap replacement and going to inspection? You should wait at least 1 week before attempting to get inspected after the computer has been cleared. Drive normally with the gas tank between 3/4 and 1/4 full. No more and no less. The readiness monitors will set and you'll be good to go. HTH. -Jim


No. There has been no check engine light at all. I went to emissions and they say there is no power when they hook up their odbc plug. There is no power to the socket under the dash. The gas cap thing was just another part of the test they run and it failed their compression test I guess. But the odbc socket has no power to it they tell me so we don't even get beyond that with the test. So it is power to that socket I need to troubleshoot.

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I see. Does the check engine light come on when you turn the ignition key on but don't start the engine? -Jim


Yes it does. with the key on but the engine off It is yellow

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The faulty gas cap should have triggered the check engine light and set a trouble code. Since the check engine light comes on I'd suspect the socket under the dash. Or a fuse. Stop by your local auto parts store and ask them to scan the computer. Most stores will do it for free. Don't tell them about your difficulty with inspection. See what they say. If they can read it then there's a problem with the inspection station. If they can't read it either the socket may be dirty or one of the wires in the socket may have backed out of the socket assembly. HTH. -Jim


This car belongs ultimately to my daughter who had a drug problem and is sober now, But when she had it she was a pig unfortunately. I pulled the plug out of the mount and it looks like perhaps a soft drink ofr something was spilled perhaps up on top of the dash board or somewhere up there and it went down and got everything all sticky. So the wires going into the back of the plug are completely sticky and gummed up. None look like they are backed out. I'm going to drench them in cleaner to get rid of the gunk. Thoughts on this new wrinkle? And again, all the fuses under the panel on the passenger side were good. Is there another place to look perhaps for a blown fuse or bad relay?

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My daughter confirmed that soda pop has gone everywhere in that car up in the dash. Oreilly confirmed with their testing tool that there is no power to that plug. It kept asking them to connect the device while it was connected. What would be the next step?

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I do have a multi-meter so I can test each wire but not quite sure how to do it or if there is a trick with the cobalt to test power to wires...or if it is pretty straight forward.

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Disconnect the negative (-) battery cable before cleaning the plug out. Use a toothbrush and some household cleaner that'll dissolve the sticky residue. I'm sure that's what the problem is. The residue is acting as an insulator and preventing the scan tool plug from making a good connection and reading the computer. Once it's clean, dry out the plug really good before you hook the battery back up. A hairdryer would be good for this. Tell your daughter congratulations for staying clean and sober. Tell her how proud you are of her too!! HTH. -Jim


Thanks! Which is the ground on that plug? I'd like to also test continuity of each wire if possible.


I'd suggest not doing that. Some of the wires go to the engine computer, some go to the airbag computer, and some go to the anti-lock brake/traction control computer (if equipped. What I'd do, now that the plug is all cleaned out, is go back to the auto parts store and have them try to scan it again. If they can you'll be all set for inspection. HTH. -Jim


We're good! Thx again


Awesome! Thanks for letting us know. -Jim


Actually not quite. ugh. So this is not my main car. It hardly gets driven. So while ADEQ connected w/o issue, the reading was 'the computer is not ready or is reset'. So I need to drive it for the computer to reset and track data I guess. So question, how long do I need to drive it, how fast, what do I need to do of a special nature if anything? Floor it? Hit 80 and hold it for a certain amount of time? And how many miles do I need to go? Any suggestions would be great

1 of 1 people found this helpful.

I just reread this thread. I got it. A week minimum or just a certain amount of mileage, or a certain amount of time at the wheel? A week is a long time and the tags expired. Don't know if I can get away with several three day temp reg's. Any alternative to a full week would be great.

1 of 1 people found this helpful.

This one's not too bad. Keep the gas tank between 3/4 and 1/4 full. No more and no less. Drive normally for about 1 week. Varying speeds, city and highway driving, that type of deal. The EVAP readiness monitor is probably going be hard to set. It always is. But here's the good news. 2000 and forward models, like your '07, will pass with 1, and only 1, readiness monitor not set. Some computers will reset faster than others. But 1 week of everyday driving, as described above, will definitely do it. HTH. -Jim

1 of 1 people found this helpful.

There is an OBD II "drive cycle" that supposedly will reset the readiness monitors in 45 minutes. I've tried it but never been successful at it. It's a rather lengthy procedure. HTH. -Jim

1 of 1 people found this helpful.

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