Can't read codes from ALDL on 83 Trans Am
#1
Can't read codes from ALDL on 83 Trans Am
Hi all,
I am getting ready to smog my 83 Trans Am next month, but I have a check engine light on, which I'm told by my smog tech that will automatically fail it,
I know about using a paperclip to jump the terminals on the ALDL, however the light will never go into diagnostics mode (Code 12).
Is there a reason why this might happen?
The car runs well and there is no obvious reason why it is throwing a code.
Any tips or ideas on getting ALDL into diagnostic mode so I would be able to check the code(s)?
Thanks
I am getting ready to smog my 83 Trans Am next month, but I have a check engine light on, which I'm told by my smog tech that will automatically fail it,
I know about using a paperclip to jump the terminals on the ALDL, however the light will never go into diagnostics mode (Code 12).
Is there a reason why this might happen?
The car runs well and there is no obvious reason why it is throwing a code.
Any tips or ideas on getting ALDL into diagnostic mode so I would be able to check the code(s)?
Thanks
#2
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Re: Can't read codes from ALDL on 83 Trans Am
There are quite a few possible reasons, starting with, the ECM is not there. (as in, someone removed it) Let's hope it's not quite that drastic.
Some history would help. When was the last time the ALDL worked? Any "repairs", modifications, etc. ever been done to the car? How long has the light been on?
Some history would help. When was the last time the ALDL worked? Any "repairs", modifications, etc. ever been done to the car? How long has the light been on?
#3
Re: Can't read codes from ALDL on 83 Trans Am
There are quite a few possible reasons, starting with, the ECM is not there. (as in, someone removed it) Let's hope it's not quite that drastic.
Some history would help. When was the last time the ALDL worked? Any "repairs", modifications, etc. ever been done to the car? How long has the light been on?
Some history would help. When was the last time the ALDL worked? Any "repairs", modifications, etc. ever been done to the car? How long has the light been on?
The ALDL has not worked since I first tried to read codes using the paper clip method about 2-3 years ago. However, the CEL has been on since I purchased the car in 2013.
The car is all stock, no modifications to the engine. It is an LG4/T5 car. Recent repairs include a new catalytic converter about a year ago and a driver side exhast manifold gasket about a month ago.
#4
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Re: Can't read codes from ALDL on 83 Trans Am
OK, so it has never worked, that you know of.
Start simple. Is the ECM present? Is it plugged in?
Start simple. Is the ECM present? Is it plugged in?
The following 2 users liked this post by sofakingdom:
NoEmissions84TA (07-21-2019), T.L. (07-18-2019)
#6
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Re: Can't read codes from ALDL on 83 Trans Am
Does it have power when the ign sw is ON? (relatively fat pink/blk wire in position C the smaller ECM connector; you can see that wire in your photo but not the pin, it's in the row behind the blk/wht gry & org, look for blk/wht then brn then that one)
ECM fuse in the fusebox good?
ECM fuse in the fusebox good?
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#8
Re: Can't read codes from ALDL on 83 Trans Am
Does it have power when the ign sw is ON? (relatively fat pink/blk wire in position C the smaller ECM connector; you can see that wire in your photo but not the pin, it's in the row behind the blk/wht gry & org, look for blk/wht then brn then that one)
ECM fuse in the fusebox good?
ECM fuse in the fusebox good?
#9
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Re: Can't read codes from ALDL on 83 Trans Am
You can get a replacement ecm on eBay for relatively cheap.
Just swap in your prom.
https://www.ebay.com/sch/i.html?_fro...3&_nkw=1226025
Just swap in your prom.
https://www.ebay.com/sch/i.html?_fro...3&_nkw=1226025
#10
Re: Can't read codes from ALDL on 83 Trans Am
Does it have power when the ign sw is ON? (relatively fat pink/blk wire in position C the smaller ECM connector; you can see that wire in your photo but not the pin, it's in the row behind the blk/wht gry & org, look for blk/wht then brn then that one)
ECM fuse in the fusebox good?
ECM fuse in the fusebox good?
You can get a replacement ecm on eBay for relatively cheap.
Just swap in your prom.
https://www.ebay.com/sch/i.html?_fro...3&_nkw=1226025
Just swap in your prom.
https://www.ebay.com/sch/i.html?_fro...3&_nkw=1226025
#12
Re: Can't read codes from ALDL on 83 Trans Am
So I tried a used ECM on Ebay and I swapped in my PROM and no dice. Still having the same issue. CEL is on and it doesn't flash when I jump with the paper clip. I started looking into the check engine light 'Lamp Driver' as suggested. Might order one to see if that solves my issue.
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