OBDII plug

Hey again,

You guys have done such a good job answering all my other questions I figured I needed to keep you busy. I've started to get into the wire harness modification and general wiring. A couple of preliminary questions:

1. Will the 2001 LS1 pinouts in the manual match my 2004 LS1 from a GTO?

2. One of my plugs is green, the other is blue. I have to identify some pins a double check that the green plug is equivalent to the red plug.

3. Since I'm taking this thing down to NH for a tune after it's running I need an OBDII port. There must be one on the harness somewhere, it's new enough. I just don't know where to find it. Is the Large black plug in the right of the first picture just for diagnostics? Will the guy at the shop be able to plug into that or do I need to splice in my own plug?

4. O2 sensors, where do they plug in, I don't see any pinouts for those.

Thanks,
Luke

Pinouts for 2004 GTO
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Sorry, that worked when I sent it. Now it needs a longin.

thanks

1. Will the 2001 LS1 pinouts in the manual match my 2004 LS1 from a GTO?

2004 GTO pin outs here: [You must be registered and logged in to see this link.]

2. One of my plugs is green, the other is blue. I have to identify some pins a double check that the green plug is equivalent to the red plug.

Huh? They are both 40 pin connectors but they are by no means carrying the same functions.

3. Since I'm taking this thing down to NH for a tune after it's running I need an OBDII port. There must be one on the harness somewhere, it's new enough. I just don't know where to find it. Is the Large black plug in the right of the first picture just for diagnostics? Will the guy at the shop be able to plug into that or do I need to splice in my own plug?

If its just the engine harness, there will be no ALDL port. You will have to create one!!! The two wires besides 12+ and ground going to the diagnostic link connector are GMLAN serial data bus which I believe (not definite) is number 58 C1. You will also need some relays and a fuse panel for all the connections.
Where/What I ordered to create my ALDL diagnostic port:

2 x relay socket PN# SRLY-2 from [You must be registered and logged in to see this link.]
2 x relays PN# RLY-351 from [You must be registered and logged in to see this link.]
8 x female connectors PN# 571-42238-2 from [You must be registered and logged in to see this link.]
4 x connector locks PN# 829-12160437 from [You must be registered and logged in to see this link.]
6 x female connectors for ALDL PN# 829-12129373 from [You must be registered and logged in to see this link.]
1 x ALDL connector PN# 829-12110250 from [You must be registered and logged in to see this link.]
2 x fuse blocks PN# DOR 85668 from [You must be registered and logged in to see this link.]

4. O2 sensors, where do they plug in, I don't see any pinouts for those.

O2 sensors are part of the main engine harness. Their pins are designated "HO2S". They are listed in the pinout sheet in the URL posted above.

Best way to do all this is with the GM factory service manual. These are found at your local main public library.

Great, thanks I'll have to look into the exact wiring for the OBDII port. I was guessing that the actual port was part of the chassis harness.

haha, no I don't mean that the two plugs are equivalent. The conversion manual lists a red plug and a blue plug, I have a green and blue. I was saying that my green is the same as the red plug. Anyway, at this point its null because I've got the pin outs for the 04 GTO so I don't need to directly reference the conversion manual for the pin outs.

which bank is front and which is rear for the O2 sensors?

What is the large black plug in the right of the picture used for? Is that the connection to the chassis harness?

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Thanks, once I dig a little deeper I'll have more questions. Right now I have to spend some more quality time with the harness, pinout diagrams and a ohm meter.

Great, thanks I'll have to look into the exact wiring for the OBDII port.

Exact Wiring for your ECU Data Link Connector:
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which bank is front and which is rear for the O2 sensors?

Bank 1 = Front
Bank 2 = Rear

What is the large black plug in the right of the picture used for? Is that the connection to the chassis harness?

That is the ASM or Accelerator Servo Control Module.

Wait a minute, I thought I had looked into that. I don't have to do drive by wire do I?

The LT1Swap guy looked at a picture of my Throttle body and knows which engine this is and said that it wasn't DBW, I wasn't sure how to tell if it was or not. I know a lot of the engines in this era were though. I think there is a servo on the throttle body, but there is also a plate for a throttle cable and it looks like that was the way it was hooked up in the GTO.

Wasn't there a whole thread about your OBDII plug wiring, I can't find it?

Wait a minute, I thought I had looked into that. I don't have to do drive by wire do I?

Im not sure but I believe this connector has something to do with traction control and such. Not DBW.

Wasn't there a whole thread about your OBDII plug wiring, I can't find it?

The only thread like that was what I posted above; part numbers and sources to make an ALDL connector.

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That's what I was thinking of, thanks

If it is DBW. Just thinking in terms of “what if” is there any reason that I can’t just hook up an old fashioned throttle cable and be on my way?
Can I just ignore the ASM plug then? I don’t plan on having traction control

If it is DBW. Just thinking in terms of “what if” is there any reason that I can’t just hook up an old fashioned throttle cable and be on my way?
Can I just ignore the ASM plug then? I don’t plan on having traction control

Well, Im not sure what throttle body you have. Post a picture of it. If it has a throttle cam, then yes. As for the ASM, I think that will be weeded out during harness modifications, but it would be good to get a definite answer as to what it does. I believe it has to do with traction control but Im not definitely sure. Maybe call your local GM dealer and ask what ASM is.

Here is an older picture of my engine. You can kinda see the TB, it does have a cam for the cable.

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If you motor was originally a DBW motor, the harness will not have the wires for the throttle position sensor.

right, I was thinking about that. There is a TPS on the TB and there was a plug going to it, so that's a good sign

Just a couple thoughts that may be useful regarding the OBDII plug:
1. I am not aware of any regulation that says the OBDII plug has to be mounted on a bracket under the driver's side dash panel. I think that is only convention. My state does not have emmisions inspections so I did not worry too much about it. What I did was to order a fully wired J1962F plug with 10' of cable. I sourced that from OBD2cables.com. This saved me the effort of having to deal with the metripak connectors that I did not have the proper crimping tools for anyway. I simply cut the 10' cable to the length I needed so splice it into the engine harness. I located mine on the passenger side so that I can pull it out easily when I want to diagnose engine codes. This is much easier than digging under the dash when you need it.
2. The 58C1 position that LT1 pointed out merely connects a wire from that point on the PCM port to the appropriate pin on one of the body harness connectors, which in turn would have lead to the OBDII connector on the original car. I found it easier to remove the body harness connectors and use those as splicing points as opposed to trying to splice at the PCM connectors, since the PCM connectors have so many wires that are bound tightly together. You will have to Ohm the wire to see which is the correct end at the body connector, but on my 2002 LS1 it was c230K, which is a dark green wire on the blue ten pin connector.

Hope that helps, just an alternate idea.

I have the GTO engine as well, an 04, that black connector was to the body control module. It took a bit of work to eliminate all the unnecessary crap, AllData really helped. When you are redoing the harness, pay attention to the fuel injector wires, they originally got their power through the body control module, at least one side did. If I remember correctly, it was the green injector power wire that I had to tie to the other side (red I think) to power one side of the engine.

Thanks for all the help guys. I'll be ripping to the harness this weekend hopefully.