OBD 2 issues
Thread Starter
Burning Brakes
Joined: Aug 2005
Posts: 779
Likes: 10
From: O'Fallon MO
2016 C4 of the Year Finalist
2015 C4 of the Year Finalist
OBD 2 issues
I have a 1994 I'm trying to get state inspected. The reader cannot communicate with the car to read the sensors. When I plug in my reader all I get is a link error. I know the reader works as I plugged it in to a different car and was able to pull information. I've checked fuses and they all seem okay.
Reader is plugged in, key in ignition, car on but not started. She has been sitting for a few months on a battery tender. Might I have shorted something?
Reader is plugged in, key in ignition, car on but not started. She has been sitting for a few months on a battery tender. Might I have shorted something?
Burning Brakes
Joined: Sep 2009
Posts: 1,003
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From: hickory NC
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'94and '95 were mongrel years for OBD. It's an OBD1 system with an OBD2 plug. Having the same issue with my '95, trying to find someone around here that can read it. Got a couple leads.
Le Mans Master
Joined: Sep 2013
Posts: 6,192
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From: near the thumb in the mitten
You do have a problem. Car is OBD1. The ALDL connector indicates PCM is reflashed there is no prom to change. GM started reflashing ecms a year or so earlier on W cars in 93. The obd will still give flash and module codes as in earlier models.
Le Mans Master
Joined: Oct 2004
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From: South-central Missouri
94 & 95 were OBD-1 with an OBD-II ALDL connector. 96 C4s were the first OBD-II C4s, (accordimg to my scanner data sheet)
Switch the reader to OBD-I if the scanner supports it and try again
Switch the reader to OBD-I if the scanner supports it and try again
Last edited by Paul Workman; May 29, 2018 at 01:36 AM.
Safety Car
Joined: Jan 2004
Posts: 4,549
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From: Glastonbury CT
Let the state inspection station bring up the codes. The Ob1 system is just a worth less code system . You can dump a ton of hours into finding codes that lead to dead ends, I know i have a 93 since new and spent many hours trying to bring codes up nothing ever came up correct. You can jump it out with a paper clip and get the same results as a $500.00 scan tool.
Thread Starter
Burning Brakes
Joined: Aug 2005
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From: O'Fallon MO
2016 C4 of the Year Finalist
2015 C4 of the Year Finalist
Thing is there are no codes....no check engine light....it just won't read the system to see all the sensors.....I keep getting a link error on my reader and the reader at the mechanics shop can't communicate with the car...
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Melting Slicks
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From: Downers Grove Illinois
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If the inspection station is having the issue - they 'don't get it' and if they're attempting 'EMISSIONS' they can't use OBD2 type connection. They should only require the 'KEY-ON/Bulb-Check' and do whatever is required for the jurisdiction to accomplish 'EMISSIONS' inspection. Varies 'jurisdiction to jurisdiction'.
There's nothing for you to do with a 'reader' that's related to EMISSIONS - You say you've 'NO CEL' - well if you have CEL/SES @ 'KEY-ON/Bulb Check > you're done.
Tell the inspector the car is OBD1 but only uses the OBD2 ALDL. They should be able to confirm that.
If NOT this then you're not explaining very well your real issue. Take another stab at the explanation. If you have a CEL/SES that stays on they're likely going to fail.
There's nothing for you to do with a 'reader' that's related to EMISSIONS - You say you've 'NO CEL' - well if you have CEL/SES @ 'KEY-ON/Bulb Check > you're done.
Tell the inspector the car is OBD1 but only uses the OBD2 ALDL. They should be able to confirm that.
If NOT this then you're not explaining very well your real issue. Take another stab at the explanation. If you have a CEL/SES that stays on they're likely going to fail.
Last edited by WVZR-1; May 29, 2018 at 10:09 AM.
Thread Starter
Burning Brakes
Joined: Aug 2005
Posts: 779
Likes: 10
From: O'Fallon MO
2016 C4 of the Year Finalist
2015 C4 of the Year Finalist
If the inspection station is having the issue - they 'don't get it' and if they're attempting 'EMISSIONS' they can't use OBD2 type connection. They should only require the 'KEY-ON/Bulb-Check' and do whatever is required for the jurisdiction to accomplish 'EMISSIONS' inspection. Varies 'jurisdiction to jurisdiction'.
There's nothing for you to do with a 'reader' that's related to EMISSIONS - You say you've 'NO CEL' - well if you have CEL/SES @ 'KEY-ON/Bulb Check > you're done.
Tell the inspector the car is OBD1 but only uses the OBD2 ALDL. They should be able to confirm that.
There's nothing for you to do with a 'reader' that's related to EMISSIONS - You say you've 'NO CEL' - well if you have CEL/SES @ 'KEY-ON/Bulb Check > you're done.
Tell the inspector the car is OBD1 but only uses the OBD2 ALDL. They should be able to confirm that.
I'll talk to them and let you guys know how it went....thanks again!
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OBD I should be a roller/sniffer test only, no need to even plug into the OBD I system.
Thread Starter
Burning Brakes
Joined: Aug 2005
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From: O'Fallon MO
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Racer
Joined: May 2018
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As others have said. Obd1 emissions is a sniffer test, not a plug in test like obd2 cars. If they’re trying to scan it for emissions they’re doing it wrong. What state are you in and where are you getting it inspected? They should have software that tells them what protocol to perform on the vehicle based on the VIN. It shouldn’t be up to you to tell them the correct testing procedures.
Thread Starter
Burning Brakes
Joined: Aug 2005
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From: O'Fallon MO
2016 C4 of the Year Finalist
2015 C4 of the Year Finalist
As others have said. Obd1 emissions is a sniffer test, not a plug in test like obd2 cars. If they’re trying to scan it for emissions they’re doing it wrong. What state are you in and where are you getting it inspected? They should have software that tells them what protocol to perform on the vehicle based on the VIN. It shouldn’t be up to you to tell them the correct testing procedures.
Race Director
Joined: Jan 2000
Posts: 16,872
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From: Owings Mills, MD 21117
First, as stated before, your '94 is OBD 1 with OBD II plug. My '93 Ruby used to go thru emissions with sniffer and treadmill until it got historic plates from state of MD and now exempt. Check with your state MVA. As long as you are not using the 'Vette as a DD you could be saving yourself $$$ on emissions and safety inspection as well as registration, tags and insurance. Good luck 
Thread Starter
Burning Brakes
Joined: Aug 2005
Posts: 779
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From: O'Fallon MO
2016 C4 of the Year Finalist
2015 C4 of the Year Finalist
Went back to the mechanics and had a talk with the head mechanic. After a long talk it turns out I don't require a emissions test. This was confirmed when we called the Highway Patrol and talked to the Chief Inspector. Only vehicles 1996 and newer are now required to pass emissions.
Thanks all as I would not have even thought about that without your help!
Thanks all as I would not have even thought about that without your help!
Le Mans Master
Joined: Aug 2015
Posts: 6,085
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From: St. Charles MO
Went back to the mechanics and had a talk with the head mechanic. After a long talk it turns out I don't require a emissions test. This was confirmed when we called the Highway Patrol and talked to the Chief Inspector. Only vehicles 1996 and newer are now required to pass emissions.
Thanks all as I would not have even thought about that without your help!
Thanks all as I would not have even thought about that without your help!