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My 97 S10 failed State emissions testing because their computer could not communicate with mine. Inspector checked the fuses and they were all good. My bluetooth elm & torque app showed live data. Took to another test station and same result, no communication. I've checked fuses, wiring, and disconnected what modules I can get access to. I have 12 volt at the dlc and the grounds checked at the dlc. I am only getting 0 to approx .6 volt on pin 2 of the dlc. From what I gather on the internet it should be between 0 and 7 volts. I've even installed a new PCM and get the same results.

Assistance on getting this resolved would greatly be appreciated.
 

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Is the computer specifically saying "not ready"/"your car’s computer is not ready to test emissions"? I'm not familiar with emissions since my state doesn't require it, but it seems from my reading that the issue is either you haven't driven it under the right conditions enough or maybe the memory in your ECM is getting wiped whenever you turn off your car.


Maybe there's a way you can verify that data is being stored correctly in your PCM between on/off cycles? I don't know if it's related to the PCM, but perhaps as an easy check you can see if the time on your car radio seems off.

Or perhaps maybe there's a parasitic drain throwing things out of whack.....
 

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Vladowman! - Not sure exactly what the message was from the inspection stations was, but they both just said there was no communication. I'm guessin that their computers were unable to determine what type of network/vehicle it was connected to. Battery checks out good and at the time of the inspection my code scanner showed that all necessary emission systems had a ready status.


Shenvannigons - Cig fuse is good and dlc pin 16 has power. Believe I even checked the voltage drop from that pin and it was good.



 

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Vladowman! - Battery checks out good and at the time of the inspection my code scanner showed that all necessary emission systems had a ready status.
I suspect it's an issue with your ECM. Your scanner connects to the same DLC that the inspection stations would have used. If your scanner is working I would think their computers would also. The connector under the dash at the DLC only has 3 wires that matter. Power, ground, and serial data. There's 3 others for Air bags, door locks, and TCCM if applicable. These are irrelevant to inspections. Well maybe not the Airbag one.
I'd go back and talk to the guys at the inspection stations and see if they know of any reason their tools won't work when your little scanner does. I'm sure they've run into this before.
 

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Took it back to the inspection station. They tried their main computer and their back up along with one of the techs hand held scanners. None were able to connect to the PCM. This is a new programmed PCM. My bluetooth scanner still connects to it. Inspector said that theirs is not able to determine what kind of vehicle/pcm it is connected to. Normally when they see this it is due to a blown or missing fuse. That is not the case with mine.

If someone has a 97 s10/astro/blazer/c1500 could you check the voltage on pin 2 of the DLC. As I have yet to find what it should actually be for that year.
 
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