2002 Sport Trac OBD Not working Fuses all good?

[Toneybrown07]

So, My 02 Sport Trac threw a check engine light today. Didn't notice anything off when driving, but took it by two auto part stores and neither could get the OBD reader to work. One said the Key needed to be turned on, which it was. The other just wouldn't connect.

Doing online searches I see a lot of people had problems with the fuse that works the OBD connector and the cigarette lighter. My fuses all seem good, and the lighter plug works.

One issue I do have with the truck is the ignition is kind of wonky. The shifter is pretty loose, and I have to push up on the shifter to be able to turn the key all the way off and pull the key out. I'm curious if something in the ignition/column could be causing the problems with the OBD reader? If I can't figure it out, I'll just live with the check engine light until I notice a performance issue I guess.

Any help would be greatly appreciated!

 

[Toneybrown07]

I went ahead and disconnected the negative terminal of the battery to reset the Check Engine light. Will wait and see if it pops back up. Still can't figure out why the ODB connector is not transmitting data.......

 

[Todd Z]

From what I remember there is actually a second fuse for it..... Need a fuse tester or volt meter and start testing.

 

[Toneybrown07]

Well, after resetting the check engine light, it stayed off for half a day. On the way home from work it came back on. Going to stop buy Autozone and have them attempt to run the code again. If that doesn't work, I guess I will look at every fuse in this sucker!!!

 

[DILLARD000]

If serious about vehicle maintenance, truely need your own OBD2 Scanner.
ELM\BlueTooth Module & ForScan+OBDLink+... apps can be had for $25~$100.

 

[Toneybrown07]

Hello everyone I'm back! So, my previous check engine light from 2022 seemingly went away on it's own without ever getting a code. Here I am in 2025 and that bastard is back. Instead of doing the auto parts store scanner, I went to a repair shop. Their assumingly better scanner still could not pull a code.

So, today I broke out the multimeter. With the key on I have 12v to the power/body ground, power and both grounds at the obd2 port. Out of curiosity I check every Obd2 connection point and they all had voltage with the power from 7-11 volts. I checked the fuses under the hood for the pcm and the relay which both seemed completely fine.

At this point I don't think there could be a wiring problem at the obd2 port. However, something is keeping it from communicating with the computer. Does anyone have an idea of where I could look next to solve this problem?

I keep going back to my previous post about the ignition. Today on the way home from work I was driving at about 60 mph and the truck instantly died. I pulled off the road, put it in park and tried to restart. When I turned the key nothing happened. I pushed up on the gear shift again, to make sure it was in park and it started right back up. I was able to drive home with no more issues. Also, my check engine light was gone, as if I had disconnected the battery.

These things seem related, but I don't have the knowledge to put the pieces together. Help! My wife wants me to buy a new truck, but this thing is still under 170K!

 

[cadman777]

Hello everyone I'm back! So, my previous check engine light from 2022 seemingly went away on it's own without ever getting a code. Here I am in 2025 and that bastard is back. Instead of doing the auto parts store scanner, I went to a repair shop. Their assumingly better scanner still could not pull a code.

So, today I broke out the multimeter. With the key on I have 12v to the power/body ground, power and both grounds at the obd2 port. Out of curiosity I check every Obd2 connection point and they all had voltage with the power from 7-11 volts. I checked the fuses under the hood for the pcm and the relay which both seemed completely fine.

At this point I don't think there could be a wiring problem at the obd2 port. However, something is keeping it from communicating with the computer. Does anyone have an idea of where I could look next to solve this problem?

I keep going back to my previous post about the ignition. Today on the way home from work I was driving at about 60 mph and the truck instantly died. I pulled off the road, put it in park and tried to restart. When I turned the key nothing happened. I pushed up on the gear shift again, to make sure it was in park and it started right back up. I was able to drive home with no more issues. Also, my check engine light was gone, as if I had disconnected the battery.

These things seem related, but I don't have the knowledge to put the pieces together. Help! My wife wants me to buy a new truck, but this thing is still under 170K!

Typically if you can't get a code reader to connect, you have issues with your CANbus.
The way to test the CANbus is shown in this video.

 

[Toneybrown07]

Typically if you can't get a code reader to connect, you have issues with your CANbus.
The way to test the CANbus is shown in this video.

Thanks for the video, unfortunately I don't have the equipment he uses. Nor the knowledge. I guess I'll just live with a light until I notice actual performance issues. Don't feel like spending probably hundreds of dollars to figure out the Obd2 problem.

 

[cadman777]

Thanks for the video, unfortunately I don't have the equipment he uses. Nor the knowledge. I guess I'll just live with a light until I notice actual performance issues. Don't feel like spending probably hundreds of dollars to figure out the Obd2 problem.

I hear ya!
But you can check the wires with a simple digital volt meter (DVM), like the cheap ones at HarborFright.
If you have shorts or continuity problems on the wires, then you can fix them and maybe that'll solve the problem.
You can get the wiring diagrams online in forums or maybe even find pdf files of them that someone has posted.
That's what I do with Asian cars like Nissan, Toyota and even Euros like VW.
Free pdf's are not hard to find online, you just have to look.
Using the DVM is 'the hard way', but that's how I did it before I got a scope.
You can also get a real cheap scope, if you have a laptop to use with it.
Start @ the 14 minute mark to see how to use the DVM.

 

[Toneybrown07]

I'll run an Ohms and voltage check on the can high and low when I get home. I found another youtube video that shows how to do this at the obd2 port.

Thanks again.

 

[cadman777]

I'll run an Ohms and voltage check on the can high and low when I get home. I found another youtube video that shows how to do this at the obd2 port.

Thanks again.

Great!
Keep us updated...

 

[Toneybrown07]

Well, ran into a snag testing the Can bus voltage. My Obd2 connection does not match up with the diagrams I have found. From what I can find pin 6 is Can High and pin 14 is Can low. My Obd2 connection does not have either of those pins........See attached photo. I do no see any loose dangling pins either.

I also unhooked the port to see the wires behind, attached are the wires coming to the port.

 

[cadman777]

Sorry for the delay.
Find attached a pic of the CANbus and DLC wiring diagram.
Remember the mantra: POWER & GROUNDS / OPENS & SHORTS.
Hope this helps...

 

[Toneybrown07]

Thanks for the diagram. If from what I have found is correct, I should get about 5v on pin 2 which I get. So the PCM is getting power. So that is good. At this point I feel like I'm gonna have to give up. If I start having actually performance issues I'll have to let the real professionals figure it out. Or listen to my wife and buy a newer truck!

 

[Toneybrown07]

Actually, I don't have 5 volts to pin 2, I have 5v to pin 10 and I have 0 volts to pin 2 and 0.33v to pin 13. So one wire to the PCM gets 5v, one is 0 and one is 0.33v. Could the fact that pin 2 has no voltage be causing my lack of a functioning Obd2?

 

[cadman777]

Actually, I don't have 5 volts to pin 2, I have 5v to pin 10 and I have 0 volts to pin 2 and 0.33v to pin 13. So one wire to the PCM gets 5v, one is 0 and one is 0.33v. Could the fact that pin 2 has no voltage be causing my lack of a functioning Obd2?

OK, here's how I read that wiring diagram:
1. You should have 12v on pin 16
2. You should have good grounds on pins 4 & 5.
3. I do not know what DLC pins 2, 10 & 13 are supposed to have in terms of voltages.
Let me look it up and see if I can find a diagram that shows it.
But for now you can check your power and grounds.
If it was me, I would visually inspect the ground connections besides DVM'ing them.
I would also do the 'wiggle' test on the wires to see if the voltages change when they're moved around.

Do you have Flex Fuel or just regular fuel injection?
I assume it's a 4.0L, right?

 

[Toneybrown07]

OK, here's how I read that wiring diagram:
1. You should have 12v on pin 16
2. You should have good grounds on pins 4 & 5.
3. I do not know what DLC pins 2, 10 & 13 are supposed to have in terms of voltages.
Let me look it up and see if I can find a diagram that shows it.
But for now you can check your power and grounds.
If it was me, I would visually inspect the ground connections besides DVM'ing them.
I would also do the 'wiggle' test on the wires to see if the voltages change when they're moved around.

Do you have Flex Fuel or just regular fuel injection?
I assume it's a 4.0L, right?

I had previously tested pin 16 and both grounds and found them all to be good. 12v to pin 16 and continuity with both grounds. All voltages were check to both grounds as well, and came back with the exact same reading for each pin tested. I removed the OBD2 port yesterday to better inspect the wires and could not find anything out of the ordinary. There has never been any wiring work done to the truck, so everything is factory.

It is not a Flex Fuel vehicle and yes the 4.0L V6

 

[cadman777]

I had previously tested pin 16 and both grounds and found them all to be good. 12v to pin 16 and continuity with both grounds. All voltages were check to both grounds as well, and came back with the exact same reading for each pin tested. I removed the OBD2 port yesterday to better inspect the wires and could not find anything out of the ordinary. There has never been any wiring work done to the truck, so everything is factory.

It is not a Flex Fuel vehicle and yes the 4.0L V6

Then you should be good on powers and grounds.

Here's the PCM wiring diagram.
it shows what those pins are so you can at least do some preliminary testing on them.

 

[cadman777]

CAN+ should be about 2.5 to 3.5
CAN- should be about 2.5 to 1.5
About 5 volts total.
I don't know if this CANbus has resistors on each end.
But if not, you shouldn't do a resistance test on it (at least that's what I read about it).

 

[cadman777]

I keep going back to my previous post about the ignition. Today on the way home from work I was driving at about 60 mph and the truck instantly died. I pulled off the road, put it in park and tried to restart. When I turned the key nothing happened. I pushed up on the gear shift again, to make sure it was in park and it started right back up. I was able to drive home with no more issues....These things seem related, but I don't have the knowledge to put the pieces together.

You're probably right.
If you do a visual inspection on your shifter and the electronics in that area (remove the plastic), you may see something that needs attention.
If my shifter was that bad, I would have replaced it already.
The reason is b/c it may be not positioning the switch that's down on the transmission.
That is just an educated guess.
Have you tried wobbling the shifter level in different directions to see if it makes the engine shut off?