Thanks for sharing the fix...so the bad IDM caused the obd port not to power up, good to know! Only had 1 true IDM go bad....and a few bad diagnosis in the past

 

Well,thats what was pissin me off. Pin 16 had power. The 2 ground pins showed a bad ground. What brought my attention to the idm was the idm relay started clickin rapidly. Although not at first. It was intermittent

 

Did you ever get your scanner to connect? I am having a simular issue on my 94, I have a modis that won't connect to the obd1 or 2 ports. Cigar lighter and maxi 22 are good

 

This is the SD 7.3L forum, so we are from the generation where OBDII is common. The '94 was pre-'96 - '96 was when the OBDII was put into full effect on most vehicles. I don't know how well the pre-'96 OBDII ports work.

You can try to set the protocol manually - SAE J1850 PWM. If the MODIS unit asks, the truck is non-OBDII compliant. I'll explain that last part: There are "universal" PIDs with universal addresses - we have extended PIDs with non-universal addresses.

 

I found this thread and hope you guys are still on here. I currently have my truck at a transmission shop and it is failing to communicate with any of thier equipment. I had some shifting issues with my 4r100 and took it in . The overdrive light has been flashing. But the truck wont communicate any codes. They are going to pull the pan and manually inspect and proceed to electrical testing if the pan shows no obvious issues. If it would just communicate the problem we would be ok. Any ideas? Thank you for your help.

 

sorry wrong thread........

 

unplug fuel bowl heater, check fuses

 

I got power in the cigarette lighter, all the fuses are fine, I already replace the IDM,but still have a problems with the obd port. Truck run like S#;€×...#$@

 

ying to find where plug goes

Trying to find where fhis goes cig lighter fuse not blown and obd2 not working used multiple obd2 found this plug under dash unplilugged but dont knkw where it goes