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Smog/Computer Question.

Backlash

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Good afternoon Folks!

I am looking for some mechanical/electrical advice from the head honcho mechanics on the boards. Here's my dilemna.

My truck is due for a smog check at a "Star" center. No big deal. I head over to a local shop and present my registration paperwork. He replies and says "No problem, should take about 10-12 minutes." Cool, thank you!

He walks up a few minutes later and tells me that his computer wont "Connect" to the vehicle's computer via the OBD-II input plug. He said he tried several times, but couldn't get the smog computer to talk with the vehicle's computer. He then takes one of his scanners out, plugs the scanner into the same OBD-II port, and the scanner is able to talk with the computer in the truck. He then tries the smog computer again with no luck. I found this odd because I haven't had any issues with the truck with regards to passing smog nor have I had any issues with the computer. I had the truck smogged two years ago without any issues.

He then backs my Suburban out of the bay and pulls a Cadillac sedan into the same spot. He takes the same smog computer plug and his PC is able to talk with the vehicle's computer. He did this just to make certain it wasn't an issue with his computer. He then backs the same Cadillac out and pulls my Suburban back into the bay. Once again, his computer is unable to connect or talk to my vehicle's computer. He backs my truck out and says it may be an issue with the OBD-II port.

He didn't charge me for the 20 minutes I was there, and said I may need to have the computer reflashed or possibly the OBD-II port replaced.

I checked the fuse that's inline with the cigarette lighter plugs on the dash because I know that might pose a problem with the OBD-II port. The fuse seems to be OK. Can you think of anything else I should look for???

Thank you for the help!!
 

Backlash

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He had a scan tool and it did connect to the computer via the OBD-II port. That's what stumps me. If the port was bad, then why was the scan tool able to connect to the computer? 🤷‍♂️
 

blownbullet

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You may want to try another shop sometimes when this happens to me I have to lift the cable up or push the cable down or jiggle it around to communicate with the vehicle either my cables worn out or the OBD two connector on your car is worn if you’re sure the fuse is good and another scanner will communicate with it maybe it’s the smog machine cable that’s worn. Good luck!
 

HALLETT BOY

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Probably the state on the other end blocking it real time ...
 

Backlash

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Thank you gentlemen! Give it a go tomorrow and see what comes of it. 👍
 

Bigbore500r

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Good afternoon Folks!

I am looking for some mechanical/electrical advice from the head honcho mechanics on the boards. Here's my dilemna.

My truck is due for a smog check at a "Star" center. No big deal. I head over to a local shop and present my registration paperwork. He replies and says "No problem, should take about 10-12 minutes." Cool, thank you!

He walks up a few minutes later and tells me that his computer wont "Connect" to the vehicle's computer via the OBD-II input plug. He said he tried several times, but couldn't get the smog computer to talk with the vehicle's computer. He then takes one of his scanners out, plugs the scanner into the same OBD-II port, and the scanner is able to talk with the computer in the truck. He then tries the smog computer again with no luck. I found this odd because I haven't had any issues with the truck with regards to passing smog nor have I had any issues with the computer. I had the truck smogged two years ago without any issues.

He then backs my Suburban out of the bay and pulls a Cadillac sedan into the same spot. He takes the same smog computer plug and his PC is able to talk with the vehicle's computer. He did this just to make certain it wasn't an issue with his computer. He then backs the same Cadillac out and pulls my Suburban back into the bay. Once again, his computer is unable to connect or talk to my vehicle's computer. He backs my truck out and says it may be an issue with the OBD-II port.

He didn't charge me for the 20 minutes I was there, and said I may need to have the computer reflashed or possibly the OBD-II port replaced.

I checked the fuse that's inline with the cigarette lighter plugs on the dash because I know that might pose a problem with the OBD-II port. The fuse seems to be OK. Can you think of anything else I should look for???

Thank you for the help!!
If it's talking to the OBD-II scanner, it's not a fuse or port connection issue.

Some vehicles have had problems "interfacing" with the states latest smog machines, in fact there have been recalls on a lot of vehicles for OBD-II "recalibration" due to difficulites like this. I believe my 2014 Volt received a recall for this, and I actually got a similar notice for my old 2003 Dodge ram (which is long gone...).

What year Suburban? I'd have the dealer run your vin # and see if there is a recall or TSB associated with your vehicle
 

Bigbore500r

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You may want to try another shop sometimes when this happens to me I have to lift the cable up or push the cable down or jiggle it around to communicate with the vehicle either my cables worn out or the OBD two connector on your car is worn if you’re sure the fuse is good and another scanner will communicate with it maybe it’s the smog machine cable that’s worn. Good luck!
Or this!!!
 

LuauLounge

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In California, there’s a state referee. Had a similar issue and contacted them. In and out in 30 minutes, passed smog and no charge.
 

SBMech

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They are having all sorts of issues with the new equipment. Hit up another shop and it will most likely be fine.

My neighbors (smog shop) have had a service rep out for their machines, both the gas analyzer BAR-97 type and the new BAR-IOS machines have needed repairs or updates weekly/bi-monthly since inception.
 

Backlash

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Thank you guys! BB, it's a 2002. Never had any problems other than some simple water pump and leaky radiator issues. 😉
 

lbhsbz

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Check the cig lighter fuse...it provides power to the Data Link Connector. Some scan tools might have their own power.
 

dribble

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Go have it checked at the Referee. If they can communicate they’ll do a regular test.
 

ka0tyk

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I had a problem connecting via my odbii port and I took some electrical contact cleaner to the port and it fixed everything after wiggling a scantool plug in there a bunch of times. Apparently the port sitting exposed for years in a state without smog mustve built some corrosion on the connectors.

If you're near OC I can spray some on it and see if my hptuners, carly, or elm327 odbii ports can connect. Theres a difference between a quick one direction code scanner and a full bidirectional. Theres canbus, J1850 +/-, etc... most basic scanners just use the serial line, a positive, and a ground.

8805CD63-7928-41F0-BA6E-98F508DE6400.jpeg
 

Backlash

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Right on thank you guys for the offers and the advice. I did check the 20 amp fuse under the hood for the cig. lighter and it was good. So the issue may be in the plug like kaotyk suggested. The scanner that he connected while at the test center looked like your Actron; but I couldn't see the brand name from where I was sitting. I will dig into it some more tomorrow morning. Thank you again, I'll keep you updated.
 
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