ODB2 port problem?

btw I also have the second Serial data wire hooked up too, to the 9 port.
Last edited by Tiago; Dec 19, 2006 at 07:34 PM.
http://www.ls2.com/boggs/torques/98pinpcm.htm
I used the pinouts to verify the wires were not cut somewhere between and they all checked out. I'm stumped.
BTW for reference though, the #9 port is not even used on the HPTuners cable. There is no prong on the connector there...... but the 98 cars have teh second searial data cable connected there
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A '94 car
A '98 PCM
A ??? harness
The harness could be your problem since as stated above they are different in a few respects from 98 to 99+. I ran into some wiring issues due to having a '98 PCM and an '03 truck harness on the motor I bought, so I bought a '98 harness.
The 98 PCM pinout I have shows two serial data lines at the PCM, C2 (Blue) #3 for a tan wire (serial data UART), and #58 for a purple wire (serial data class 2).
Here's my .02 as to your problem:
If I recall my computerese correctly, UART stands for Universal Asynchronous Receiver Transmitter, so the tan wire not present on your HPT cable is what is used to talk to and listen from the PCM for the '98 PCM. I don't know about HPT stuff, but I would think the cables would not interchange since the later cars don't use the #9 pin on the connector. Maybe someone w/ HPT expertise can advise on this.
Somewhat related, I also looked at my diagram for the '95 LT1 swap I did in my Datsun, and the OBD1 connector uses two serial type wires in additon to one power and two grounds like the '98 does.
A '94 car
A '98 PCM
A ??? harness
The harness could be your problem since as stated above they are different in a few respects from 98 to 99+. I ran into some wiring issues due to having a '98 PCM and an '03 truck harness on the motor I bought, so I bought a '98 harness.
I was wondering what the tan #9 wire does on a '98? The OBD2 connector I bought (from a newer F-body) doesn't have it.
The 98 PCM pinout I have shows two serial data lines at the PCM, C2 (Blue) #3 for a tan wire (serial data UART), and #58 for a purple wire (serial data class 2).
Here's my .02 as to your problem:
If I recall my computerese correctly, UART stands for Universal Asynchronous Receiver Transmitter, so the tan wire not present on your HPT cable is what is used to talk to and listen from the PCM for the '98 PCM. I don't know about HPT stuff, but I would think the cables would not interchange since the later cars don't use the #9 pin on the connector. Maybe someone w/ HPT expertise can advise on this.
Somewhat related, I also looked at my diagram for the '95 LT1 swap I did in my Datsun, and the OBD1 connector uses two serial type wires in additon to one power and two grounds like the '98 does.
I have a modified 98 harness on the car, it the four wires present in the ODB2 connector have been verified correct. My only other lead is the PCM itself.
Did you check the fuse for your cigarette lighter?If it's blown then you'll have no power to your ALDL,as they run off the same 12v circuit..Just something to check.
Do a continuity check to confirm that pin 2 of the ALDL is making it to pin 58 of the BLUE PCM connector.
Use a voltmeter from pins 4 & 5 to pin 16 of the ALDL to confirm that 12 volts is there.
Make sure all terminals are fully seated in the connectors (especially pin 58 in the PCM).
If all of that is ok substitute a different 98 PCM and see if it works.
The UART serial data line doesn't matter for this, only the Class 2 serial data line matters.
One of the above has to be the problem, there are no other wires or magic involved.

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Do a continuity check to confirm that pin 2 of the ALDL is making it to pin 58 of the BLUE PCM connector.
Use a voltmeter from pins 4 & 5 to pin 16 of the ALDL to confirm that 12 volts is there.
Make sure all terminals are fully seated in the connectors (especially pin 58 in the PCM).
If all of that is ok substitute a different 98 PCM and see if it works.
The UART serial data line doesn't matter for this, only the Class 2 serial data line matters.
One of the above has to be the problem, there are no other wires or magic involved.
BTW I used a circuit tester and a multimeter to check all these wires.
thanks!
Last edited by Tiago; Jan 3, 2007 at 09:23 AM.
Blue connecter
The 1998 Harness is wired for two wires:
#3 - Tan SD-UART
#58 - Ppl SD-CII
Blue connecter
The 1999 setup has one wire:
#58 -DkGrn SD
(but the haynes diagram shows it to be just the opposite!!!)
So be weary of your source info!!!
As for my delimma, this thread answered it. The 1999 #58 -Dk Grn Serial Data wire should link with the Purple 1998 #58.







