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Discussion Starter #1
So the ECS is not functioning...flashing Sport/Tune lights..,.and when I went to diagnose it using the OBD1 port, I got no readings from the port (pin 3 and pin 12). Then I checked for engine codes (pin 1 and pin 12). Also nothing. I tried with a home made test light and now a brand new multi meter.

Nothing obvious out of place. Where do I start with this?
 

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I am not even sure if you can read anything from the ECS computer through OBD1, i could be wrong on that though.

It's a pretty good chance that its the ECS computer itself if it has never been touched. When mine went out i had the same issue and i ended up just unplugging it becuase it would default to sport and the roads here were terrible to daily it like that. You can always pull the computer and visually inspect. Not sure if you can do any bench tests on them.
 

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According to the manual you can. Pin 3 positive and pin 12 negative should show fault codes. We just got the computer out of a SL with ECS this past weekend as ours didn't have a controller when we bought it. What concerns me though is we can't read the ECM codes either. It's almost like the entire OBD1 port is out.

Looked at fuses just to verify. Would seem really odd to have two wires busted and both happen to be going to the OBD port. Can't see where that ties into the rest of the loom...unless we take off the dash...was wondering if there may be something unplugged somewhere.

jrhorne, where in SoCal are you? We're in Temecula/Murrieta area.
 

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According to the manual you can. Pin 3 positive and pin 12 negative should show fault codes. We just got the computer out of a SL with ECS this past weekend as ours didn't have a controller when we bought it. What concerns me though is we can't read the ECM codes either. It's almost like the entire OBD1 port is out.

Looked at fuses just to verify. Would seem really odd to have two wires busted and both happen to be going to the OBD port. Can't see where that ties into the rest of the loom...unless we take off the dash...was wondering if there may be something unplugged somewhere.

jrhorne, where in SoCal are you? We're in Temecula/Murrieta area.
Are you using this method to try and read ECU codes?

https://www.stealth316.com/2-diagcodes91-93.htm

Does the car still run, no CEL, so the ECU seems OK? I have no idea where to even start to try and diagnose an issue with the OBD1 port itself.

I would just pull the ECS computer from the back and visually inspect it if you havent yet. Mine was visually burned like when my original ECU caps leaked and fried the board.

edit: I am in orange county.
 

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Discussion Starter #5
Are you using this method to try and read ECU codes?

https://www.stealth316.com/2-diagcodes91-93.htm

Does the car still run, no CEL, so the ECU seems OK? I have no idea where to even start to try and diagnose an issue with the OBD1 port itself.

I would just pull the ECS computer from the back and visually inspect it if you havent yet. Mine was visually burned like when my original ECU caps leaked and fried the board.

edit: I am in orange county.
Yea, it's the whole port. Car starts and runs fine...really good and strong actually though it's getting new plugs, wires, lifters, and a 60K within the next month and just got new oil yesterday just to make sure we know the service schedule...but the OBD port is dead.

Looking at the wiring diagram...for what seems like days now...I think I just had an epiphany...I am looking at the diagram of the wiring junction in the service manual and noticed there are a number of plugs on it for the different wiring harnesses. The ones on the backside are just labeled to body wiring harness...not specific to anything.

But then I looked at the wiring diagram of the junction box itself and noticed something...I can see where the wires going to the OBD port are in the junction box and they go to a spot called E...and E looks like the OBD connector. Then looking at the diagram of the rear of the junction box I see a port there for one of the "body wiring harnesses" marked E...

Now I haven't verified it yet but I wonder if THAT E is where the wiring for the OBD port plugs into the junction box? If so, and if that isn't plugged in, that would account for why the port isn't working! Will have to check it tonight if I can. It seems like its' really high on the junction box and I won't be able to reach it unless I drop the junction box out the bottom of the dash.
 

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Nevermind. Looking at the wiring diagram it's hard to tell WHERE this could be routed. I don't think that junction box connection is only for the OBD port.
 
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