reading an ECM
Thread Starter
Racer
Joined: Aug 2014
Posts: 287
Likes: 9
From: Toledo
reading an ECM
Hello all, I just purchased a second ECM for my 95 vett so that I can do some tuning or just a backup for "just in case". If I want to use my OBD scanner to read the new ECM do I need to plug in all 4 of the connectors of the ECM? Im just worried about plugging something in that hopefully is not F' up. The ECM is the same part number (so the sticker says). what I would like to do is to read whats in it to verify before I do a download to my original.
Im wondering how could one bench test on of these? I guess you would need the correct connect(s) (red, black, white, blue) but not sure which ones and if all are needed.
Im wondering how could one bench test on of these? I guess you would need the correct connect(s) (red, black, white, blue) but not sure which ones and if all are needed.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
To read the EEPROM in the PCM you would need to power up enough power inputs so that the EEPROM gets power, plus whatever communications components are used to interface with the ALDL connector. The inputs are pretty well protected, so it would be hard to hurt the PCM.
To bench test an ECM/PCM you need to fool it into thinking it is connected to an engine. That means simulating all the sensors and other inputs. My setup looks like this for my 1227165 ECM:
It also helps to have a logic analyzer so you can see what the ECM/PCM is doing:
To bench test an ECM/PCM you need to fool it into thinking it is connected to an engine. That means simulating all the sensors and other inputs. My setup looks like this for my 1227165 ECM:
It also helps to have a logic analyzer so you can see what the ECM/PCM is doing:
Last edited by Cliff Harris; Jul 8, 2015 at 12:07 AM.
Thread Starter
Racer
Joined: Aug 2014
Posts: 287
Likes: 9
From: Toledo
To read the EEPROM in the PCM you would need to power up enough power inputs so that the EEPROM gets power, plus whatever communications components are used to interface with the ALDL connector. The inputs are pretty well protected, so it would be hard to hurt the PCM.
To bench test an ECM/PCM you need to fool it into thinking it is connected to an engine. That means simulating all the sensors and other inputs. My setup looks like this for my 1227165 ECM:
It also helps to have a logic analyzer so you can see what the ECM/PCM is doing:
To bench test an ECM/PCM you need to fool it into thinking it is connected to an engine. That means simulating all the sensors and other inputs. My setup looks like this for my 1227165 ECM:
It also helps to have a logic analyzer so you can see what the ECM/PCM is doing:
Hi Cliff, I noticed I had never thanked you. Thank you. That's what I was talking about. maybe when I retire ill have time to monkey with something like that. That is an impressive setup. Wait a second.. is that in your bathroom?? LOL
Last edited by chadk; May 5, 2016 at 07:54 PM. Reason: spell
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
I have two dressing areas on each side of my bathroom. This is the one I don't use.
Team Owner
Joined: Sep 2003
Posts: 25,393
Likes: 2,741
Very few ACD jobbers or dealers purchased the hardware required to program the PCM on the bench and confirm the software load. Many likely don't have personnel familiar with it to use it if it were all there.
Some auto parts jobbers (NOT the chains) have the capability to program and bench check the PCMs. You might get lucky and a local ACD jobber is a participant in the GM/ACD program and could help you.
Call around and find someone local that can do the bench check or programming. I would expect that you'l need to have the PCM loaded with the software match to even confirm it's good hardware. It will either except the programming or not and if it does then is it OK?
Someone with the correct bench equipment should be able to SCAN for the ID load as it is. DO you have the VIN for the car it was removed from?
The PCM even though it's the correct hardware match requires different equipment to program, read and edit. I don't know of a DIY that does it all. Never looked thought either.
Some auto parts jobbers (NOT the chains) have the capability to program and bench check the PCMs. You might get lucky and a local ACD jobber is a participant in the GM/ACD program and could help you.
Call around and find someone local that can do the bench check or programming. I would expect that you'l need to have the PCM loaded with the software match to even confirm it's good hardware. It will either except the programming or not and if it does then is it OK?
Someone with the correct bench equipment should be able to SCAN for the ID load as it is. DO you have the VIN for the car it was removed from?
The PCM even though it's the correct hardware match requires different equipment to program, read and edit. I don't know of a DIY that does it all. Never looked thought either.
Drifting
Joined: May 2013
Posts: 1,736
Likes: 31
From: Reno Nevada
Team Owner
Joined: Sep 2003
Posts: 25,393
Likes: 2,741
Maybe I missed something here, but to use any of the editing etc it requires an "in car" connection and I thought the OP was interested in confirming he's bought a functional piece of hardware. Did I miss something here? Just interested!
That was why I asked if he had the VIN of the car it was removed from, if the VIN was a match/or similar then maybe it could be installed and scanned for confirmations. If it's an "unknown" then do you just install and "cross-fingers"?
Does the OP just need to be sure there's a "knock module" in the PCM and install?
Maybe just installed, "key-on" to scan for code?
Like I said - just interested and I've read some rather conflicting information previously so ......
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