'03 5.3L OBD II problem

[Hunt]

I have a 97 TJ with a 2003 5.3L out of a full size Chevy truck. I bought the Jeep with the conversion done. The harness and computer programing came from Wait4Me Performance. I'm trying to plug a standard OBD II scanner into the OBD II port under the driver's side dash. All I want to do is read codes because the engine is running rich. The scan tool does not even power up. It works on my daily driver so I know it is not the tool. I got to looking at the port connection and it looks like it may be pinned incorrectly. I have called and emailed Wait4Me but have gotten no response and the phone mailbox says its full and not accepting messages. The pins I have are
Pin 3- Purple
Pin 4- Black w/ Blue stripe
Pin 5- Black w/ Tan stripe
Pin 6- Green
Pin 7- Pink
Pin 10- White w/ Black stripe
Pin 16- Pink w/ While stripe

The industry standard 7 pins are 2,4,5,7,10 and 16. I have +12V power at pin 16 like I should. I checked all my fuses just in case.

What I am asking for is if someone with a factory wiring diagram of the OBD II port would share the pinning and color info. Or someone with the truck would take a look at their port and let me know. Anyone with a little insight on this would be greatly appreciated.

Thanks
Hunt

[84zz4ss]

Pin
Wire Color
Circuit No.
Function

1
--
--
Not Used

2
PPL
1132
DLC Class 2 Serial Data

3
--
--
Not Used

4
BLK
1050
Ground

5
BLK/WHT
451
Ground

6-15
--
--
Not Used

16
ORN
640
Battery Positive Voltage

This is from the 03 5.3 silverado manual. Hope it helps.

[Bo185]

Originally Posted by Hunt

I have a 97 TJ with a 2003 5.3L out of a full size Chevy truck. I bought the Jeep with the conversion done. The harness and computer programing came from Wait4Me Performance. I'm trying to plug a standard OBD II scanner into the OBD II port under the driver's side dash. All I want to do is read codes because the engine is running rich. The scan tool does not even power up. It works on my daily driver so I know it is not the tool. I got to looking at the port connection and it looks like it may be pinned incorrectly. I have called and emailed Wait4Me but have gotten no response and the phone mailbox says its full and not accepting messages. The pins I have are
Pin 3- Purple
Pin 4- Black w/ Blue stripe
Pin 5- Black w/ Tan stripe
Pin 6- Green
Pin 7- Pink
Pin 10- White w/ Black stripe
Pin 16- Pink w/ While stripe

The industry standard 7 pins are 2,4,5,7,10 and 16. I have +12V power at pin 16 like I should. I checked all my fuses just in case.

What I am asking for is if someone with a factory wiring diagram of the OBD II port would share the pinning and color info. Or someone with the truck would take a look at their port and let me know. Anyone with a little insight on this would be greatly appreciated.

Thanks
Hunt

If the reader isn't even turning on then check and see which pin has 12v and which has the ground now. Seems like its pinned wrong?

[Hunt]

The serial data connection is located at pin 52 on the blue connection to the PCM. I used my Fluke to ring out a few of the loose ended wires from the Wait4Me harness. By shear luck I found the correct wire. I opened up the stock OBD II port and stole a pin from the factory Jeep plug to wire pin 52 to. According to the GM wiring schematics that line needed to go to pin 2 on the port. I needed to ground 2 of the stock Jeep wires in the plug to cancel out the cross talk and I now have a working OBD II port. There are two codes on the scan tool and I will be working on those. If I can get this thing to run a little leaner it will be a real screamer.
I also figured out how the brown wire works. It’s actually a ground that is switched through the computer. I need to hook up a positive from the key to a light and the brown wire would act as a ground. If there is a code thrown the computer closes the circuit and the light comes on. Pretty simple. I just need to pick up a cheap light.

Thanks for all the help. Turns out it was just a couple of connections that were never made in the harness.

[Bo185]

Originally Posted by Hunt

The serial data connection is located at pin 52 on the blue connection to the PCM. I used my Fluke to ring out a few of the loose ended wires from the Wait4Me harness. By shear luck I found the correct wire. I opened up the stock OBD II port and stole a pin from the factory Jeep plug to wire pin 52 to. According to the GM wiring schematics that line needed to go to pin 2 on the port. I needed to ground 2 of the stock Jeep wires in the plug to cancel out the cross talk and I now have a working OBD II port. There are two codes on the scan tool and I will be working on those. If I can get this thing to run a little leaner it will be a real screamer.
I also figured out how the brown wire works. It’s actually a ground that is switched through the computer. I need to hook up a positive from the key to a light and the brown wire would act as a ground. If there is a code thrown the computer closes the circuit and the light comes on. Pretty simple. I just need to pick up a cheap light.

Thanks for all the help. Turns out it was just a couple of connections that were never made in the harness.

Now that wasn't that hard now was it! Congrats and Good luck.

You can get a cheap Yellow LED at Radio shack for around a couple of bucks. It will be already wired and ready to go.