No power to OBD plugin port

Troubleshooting
1

Hi everyone, Gary here from Portland Oregon USA
I have a 1992 3000 GT VR4… I have just done a restore on this one and have 3 issues.

I will speak of #1 issue only in this post, If I can fix this, I might be able to tackle the others.

I have no power to the OBD #1 pin which I understand to be the main power pin to fire up my scanner. I have checked fuses to the cigarette lighters and also the fuse to the interior lights. All work fine, any ideas as to what next? I am 67 and my eyes are tired so I really want to fix the plug and not be chasing little pins with clips and jumpers. Thanks for your time and help guys. Joe, you keep up the great work your doing a fantastic job.

PS I have 4 more of these 1st gens to restore after this one. Anyone living in the Great NW USA. I wound love to hookup for help and parts if they would like.

NO HELP WILL BE GIVEN WITHOUT PROVIDING AS MUCH INFORMATION AS POSSIBLE RELATING TO YOUR ISSUE

1 Like
2

stealth316.com’s library section has a good explanation of the 1st gen plug output. To summarize, you need to connect pin 10 and pin 12 together (pin 12 is ground). That puts the output of pin 1 into scan tool mode.

Otherwise, without pins 10-12 shorted, you can use an analog (not digital) voltmeter and measure the voltage pulses on pin1, then look up the codes in the service manual.

3

The OBD1 diagnostic port does not provide power (like the OBD2 port does).
Pin 1 is the communication port of the engine ECU.
What pbleile described earlier is accurate.