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Will not start, OB2 reads no-link?

Tiny
WILLIAM HUGHES
  • MEMBER
  • 1999 FORD F-250
  • 5.4L
  • V8
  • 4WD
  • AUTOMATIC
  • 5 MILES
Put a rebuilt motor and transmission in, it has less than 5 miles on it. Now it will not start or turn over ob2 reads no-link. Replaced PCM still reads no-link. Replaced it again still reads no link. Took it to auto repair place they can't figure it out and they are very good mechanics.
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Friday, October 1st, 2021 AT 10:43 AM

11 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good afternoon,

I attached the wiring diagram for you of the system with the powers to the PCM. Verify there are powers to the pins for power and the grounds need to be verified as well.

https://www.2carpros.com/articles/how-to-check-wiring

https://www.2carpros.com/articles/how-to-use-a-voltmeter

https://www.2carpros.com/articles/how-to-check-a-car-fuse

When you turn the key to the on position, does the check engine light come on?

https://www.2carpros.com/articles/car-cranks-but-wont-start

Roy
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Friday, October 1st, 2021 AT 11:02 AM
Tiny
WILLIAM HUGHES
  • MEMBER
  • 5 POSTS
Oh, one more thing on the ob2 I have power on pin 16 and ground on 4 and 5 that seems to be what everyone asks me. But I always thought if the ob2 tool reads no-link it has to have power and ground. Or maybe I am wrong.
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Friday, October 1st, 2021 AT 11:03 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
You need the power to pin 16 and pin 4. That will power up the scan tool.

This is a different issue.

Roy
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Friday, October 1st, 2021 AT 11:04 AM
Tiny
WILLIAM HUGHES
  • MEMBER
  • 5 POSTS
Yes, the engine light comes on and I can hear the gas pump running.
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Friday, October 1st, 2021 AT 3:32 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Then there is nothing wrong with the PCM.

You need to start unplugging components to see if it starts to communicate.

Sensors are a good start.

Roy
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Friday, October 1st, 2021 AT 4:04 PM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Just to jump in on this one as I have seen this a couple times. First, we need to know if this specific scan tool has ever communicated with this truck before? Also, the shop that you took it too, they had the same issue of not being able to communicate with the PCM?

Next, we need to check the voltage on pin 13 at the DLC. If you are not getting any voltage, then go to the PCM and check on the same wire to see if anything is coming out of the PCM.

Next check voltage on pin 2 and ground. Then 10 and ground.

https://www.2carpros.com/articles/how-to-check-wiring

If you look at the wiring diagram, it is possible you have an issue with the cluster that is corrupting communication as Roy mentioned so you can try unplugging that and see if you can communicate with the PCM.

The NGV module that is shown as well is natural gas module, so you most likely don't have that module. If you do, unplug that as well. It may be there even if this is not a NGV truck.

If you have replaced the PCM multiple times and it is not communicating, then that leaves a scan tool issue or wiring issue.

So, let's check each of these pins for voltage and go from there. Thanks
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Saturday, October 2nd, 2021 AT 6:53 AM
Tiny
WILLIAM HUGHES
  • MEMBER
  • 5 POSTS
I will do that soon I hope once I go get it back from the mechanics I rather fix it myself to save money. I will let you know the outcome when I test what you have mentioned. The scan tool was used on this truck before with no problem and it also works on my wife's car. The mechanics scan tool does the same thing no-link.
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Saturday, October 2nd, 2021 AT 7:27 AM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Okay. So that just confirms that we have corruption or a wiring issue so, yes. Let us know what you find and Roy or myself will get back to you.

Thanks for the update.
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Saturday, October 2nd, 2021 AT 8:19 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
We have not heard back from you. Just checking for any update.

Roy
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Thursday, October 7th, 2021 AT 1:49 PM
Tiny
WILLIAM HUGHES
  • MEMBER
  • 5 POSTS
No update. I don't have the money to get it back from auto repair place I had other work done on it. So maybe next month money been a pian in the thing lately but I hope will be better soon. But thanks for asking I saved the few answers that you all have sent me this is a doozy of a problem. I hope one of you has nail it and when I find out I will let you know or if I do end up taking it to the dealers I will let you all know the outcome because I don't want this to happen to anyone else that way one or all of us can help the next pour sob that this happens to. Thanks
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Thursday, October 7th, 2021 AT 2:39 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
You are welcome.

Keep us updated with the results.

Roy
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Thursday, October 7th, 2021 AT 2:44 PM

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