dreaded Po720 code questions
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Freshman User
Joined: Sep 2007
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From: So. Cal.
dreaded Po720 code questions
Hello folks,
i know this question is been tossed around a lot about this stupid code. I need a good wiring diagram from anybody or a source for a new harness I drive a 2003 4x4 with the 5r110W and my local dealer tells me they're obsolete. couldn't even get me a harness diagram. Also, does the transmission have any ground wires connected to it from the chassis?
Currently going thru thru the harness to check for breaks or melted wires etc. its a big O'l mess! Please help! Thanks.
Little back story.
had the original tranny and the tow button light would flash periodically noticed a slight slippage on 3rd gear at the same time ( figured they were connected somehow) truck does have 380K so figured it was time to start looking for a new tranny. opportunity came to buy a "good" used one and I did. I installed it and this one will not only slip on 3rd gear it stays there. I have to shut the motor off and re-start the truck for it to go into 1st gear again. also once it slips and stays at 3rd gear my rpms are high. around 800. So my best guess that it wasn't the tranny that had an issue and more of a wiring problem.
i know this question is been tossed around a lot about this stupid code. I need a good wiring diagram from anybody or a source for a new harness I drive a 2003 4x4 with the 5r110W and my local dealer tells me they're obsolete. couldn't even get me a harness diagram. Also, does the transmission have any ground wires connected to it from the chassis?
Currently going thru thru the harness to check for breaks or melted wires etc. its a big O'l mess! Please help! Thanks.
Little back story.
had the original tranny and the tow button light would flash periodically noticed a slight slippage on 3rd gear at the same time ( figured they were connected somehow) truck does have 380K so figured it was time to start looking for a new tranny. opportunity came to buy a "good" used one and I did. I installed it and this one will not only slip on 3rd gear it stays there. I have to shut the motor off and re-start the truck for it to go into 1st gear again. also once it slips and stays at 3rd gear my rpms are high. around 800. So my best guess that it wasn't the tranny that had an issue and more of a wiring problem.
Fleet Owner
Joined: Apr 2012
Posts: 27,307
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From: Spanaway
Damage can be hidden under insulation.
Also call and talk to Ed or Scott and see if they can find you that harness.
https://www.ficmrepair.com
Also call and talk to Ed or Scott and see if they can find you that harness.
https://www.ficmrepair.com
Thread Starter
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Freshman User
Joined: Sep 2007
Posts: 27
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From: So. Cal.
Thanks for all your help. wires had continuity on both ends of the wire with no visible cut wires. If there's an issue with one of the wires it's probably broken strands somewhere (like you said. "under the insulation). Wish there was a way to put some volts on the wire to test the resistance. I ended up cleaning all the plugs and connectors with spray and dielectric grease. plugged everything back in and transmission is shifting and running perfect. I'm crossing my fingers it stays that way. Also going to change the alternator just in case. I'll keep you posted. thanks again for all your help.
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Fleet Owner
Joined: Apr 2012
Posts: 27,307
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From: Spanaway
Good to hear you got it working for you.
As for changing the throttle assembly I bet the part you take off will be good and your just spending money on a problem
that is not really there. I would give it a week or two. There are three variable resistors in the assembly. You might get a ODB2
dongle and Forscan to see what it's doing.
As for changing the throttle assembly I bet the part you take off will be good and your just spending money on a problem
that is not really there. I would give it a week or two. There are three variable resistors in the assembly. You might get a ODB2
dongle and Forscan to see what it's doing.
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Freshman User
Joined: Sep 2007
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From: So. Cal.
Wasn’t going to replace the throttle assembly. I’m replacing the Alternator and It has a warranty so no out of pocket expenses. I gotta find somebody with the forscan around or near me. SoCal. It’s a bit pricey around me.
Fleet Owner
Joined: Apr 2012
Posts: 27,307
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From: Spanaway
https://forscan.org/home.html
You can get the software fro free. So that only costs you for the OBD2 dongle.
That is only about a $30ish item.
You can get the software fro free. So that only costs you for the OBD2 dongle.
That is only about a $30ish item.
FTE Leadership Emeritus
Joined: Sep 2003
Posts: 12,253
Likes: 763
From: Houston, Texas
I was VERY fortunate to get a new transmission harness after the transmission shop that rebuilt my transmission hacked mine up trying to fix a hardware problem they caused.
They found one in Livonia (One of Ford's transmission plants) and sent it to me. It was no easy find, they had them all day for 2005-2007 Super Duty but not my 2005 Excursion.
It'll probably require a little work but I'm sure you can find one.
They found one in Livonia (One of Ford's transmission plants) and sent it to me. It was no easy find, they had them all day for 2005-2007 Super Duty but not my 2005 Excursion.
It'll probably require a little work but I'm sure you can find one.
Hotshot
Joined: Dec 2014
Posts: 17,832
Likes: 3,119
From: Jersey Shore
That's not good to hear. It means they have exhausted all the inventory and no contract with the supplier to build more. Well, maybe not - if the demand is there they could possibly unless the supplier tossed the setup.
Thread Starter
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Freshman User
Joined: Sep 2007
Posts: 27
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From: So. Cal.
I was VERY fortunate to get a new transmission harness after the transmission shop that rebuilt my transmission hacked mine up trying to fix a hardware problem they caused.
They found one in Livonia (One of Ford's transmission plants) and sent it to me. It was no easy find, they had them all day for 2005-2007 Super Duty but not my 2005 Excursion.
It'll probably require a little work but I'm sure you can find one.
They found one in Livonia (One of Ford's transmission plants) and sent it to me. It was no easy find, they had them all day for 2005-2007 Super Duty but not my 2005 Excursion.
It'll probably require a little work but I'm sure you can find one.
Yeah, I tried my local Ford dealer with no luck. They just flat out said it was “obsolete” They gave me a number to a guy it’s on one of the replies to this same post where I can maybe find a harness. Have t tried the number so not sure if it’s new or used. But if I have any more problems I’ll definitely give them a call. Good luck with yours.
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Freshman User
Joined: Sep 2007
Posts: 27
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From: So. Cal.
https://forscan.org/home.html
You can get the software fro free. So that only costs you for the OBD2 dongle.
That is only about a $30ish item.
You can get the software fro free. So that only costs you for the OBD2 dongle.
That is only about a $30ish item.
Awesome man! Thanks for all the info! I’ll definitely get me a Dongle. I’m just using my SCTLivewire monitor
Frmr Ford Trans Engr
Joined: Aug 1999
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From: SE Florida
That's where my office was from 1988-2007.