TFT Error - How do I test?
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Fleet Mechanic
Joined: Aug 2005
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TFT Error - How do I test?
I got this issue with the flashing tow/haul mode light 20,000 miles ago. I threw in a new TFT sensor, problem went away. Now it's back. I put in a new Ford sensor and same problem. I test it with the pan off. I get random wierd temperatures like -9, 0, -68, 23, etc. I even bought an oreilly temp sensor just in case the new ford one was bad. I have zero chafing issues on the external harness. It's lived in the garage it's whole life, and even the loom/conduit plastic is still pliable. The wires are all intact to the engine.
Still, the issue remains.
Currently I am getting -68 degrees according to forscan, which typically means the truck is simply not seeing the temperature reading at all. It's dead as far as it's concerned.
BUT....
I tested the TFT circuit.
Probing...
TFT sensor pins: 26 Ohms
Bulkhead pins 18/22 on transmission: 26 Ohms
PCM "Connector B" pins 26/30: You guessed it, 26Ohms.
So the sensor is sending a reading all the way to the PCM. I don't know what happens after that point but whatever it is, the truck gauges, Forscan, SCT isn't seeing it either.
Does this definitively mean my PCM is shot?
I have not had a chance to talk to Ed at FicmRepair. He's top notch, so maybe he should be my next stop.
Still, the issue remains.
Currently I am getting -68 degrees according to forscan, which typically means the truck is simply not seeing the temperature reading at all. It's dead as far as it's concerned.
BUT....
I tested the TFT circuit.
Probing...
TFT sensor pins: 26 Ohms
Bulkhead pins 18/22 on transmission: 26 Ohms
PCM "Connector B" pins 26/30: You guessed it, 26Ohms.
So the sensor is sending a reading all the way to the PCM. I don't know what happens after that point but whatever it is, the truck gauges, Forscan, SCT isn't seeing it either.
Does this definitively mean my PCM is shot?
I have not had a chance to talk to Ed at FicmRepair. He's top notch, so maybe he should be my next stop.
Thread Starter
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Fleet Mechanic
Joined: Aug 2005
Posts: 1,689
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Codes? You want CODES? Brother, I got codes!
===TCM DTC P0710-FF===Code: P0710 - TFT circuit range/performance problem Module: Transmission Control Module Diagnostic Trouble Code===END TCM DTC===
===TCM DTC P0713-FF===Code: P0713 - TFT Sensor Circuit High Voltage InputModule: Transmission Control Module Diagnostic Trouble Code===END TCM DTC===
===PCM DTC P0683-60===Code: P0683 - Glow Plug Control Module Communication Fault Status: - DTC Present at Time of Request - Malfunction Indicator Lamp is Off for this DTC Module: Powertrain Control Module Diagnostic Trouble Code===END PCM DTC===
===PCM DTC P0700-60===Code: P0700 - Transmission Control System malfunction Status: - DTC Present at Time of Request - Malfunction Indicator Lamp is Off for this DTC Module: Powertrain Control Module Diagnostic Trouble Code===END PCM DTC===
===OBDII DTC P0713-P===Code: P0713 - TFT Sensor Circuit High Voltage Input Status: - Pending - malfunction is expected to be confirmed Module: On Board Diagnostic II Diagnostic Trouble Code ===END OBDII DTC===
I will check those two wires against ground for continuity tomorrow.
More Turbo
Joined: Nov 2009
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From: Kansas
Hotshot
Joined: Dec 2014
Posts: 17,831
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From: Jersey Shore
Resistance testing wires is only applicable if you have a milliohm meter, and many people, including tech's, do not.
Load testing is preferred if you know how to do it.
There are two video links. People bring cars to him, even towed, from all over the East Coast because he is that good. I won't pick one video, but here is his site.
https://www.youtube.com/@PineHollowA...nostics/videos
The second video source is one I did about grease conductivity (short story; anything works). In it, I show how a milliohm meter can be used to check if a wire is partially broken, which, when under load, would affect the sensor readings.
Load testing is preferred if you know how to do it.
There are two video links. People bring cars to him, even towed, from all over the East Coast because he is that good. I won't pick one video, but here is his site.
https://www.youtube.com/@PineHollowA...nostics/videos
The second video source is one I did about grease conductivity (short story; anything works). In it, I show how a milliohm meter can be used to check if a wire is partially broken, which, when under load, would affect the sensor readings.
Thread Starter
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Fleet Mechanic
Joined: Aug 2005
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I think I am getting closer.
I carefully backprobed everything and didn't get anywhere. However, as I was fiddling around, when I plug in my PCM connector, i breifly get a reading on Forscan. As you move that lever closed to lock, the readings get erratic and then go to nothing. But now I don't know if the issue is the connector at the PCM or the PIN in the PCM. I can't test that. Either way, the issue is at the connection right there and I'm now leaning toward that connector on the end of the external harness.
Either way, the external harness is discontinued, so where can I get the connector on the end and fix just that?
Maybe I can spray some Deoxit in the end and see if whatever is not clamping down will loosen up...Not sure.
Every time I unplug the connector and plug it back in, I get no reading, or 5 degrees, or 150 degrees. The connector itself seems fine. Everything about this is screaming bad solder joint in the PCM. I have no other explanation for this.
I carefully backprobed everything and didn't get anywhere. However, as I was fiddling around, when I plug in my PCM connector, i breifly get a reading on Forscan. As you move that lever closed to lock, the readings get erratic and then go to nothing. But now I don't know if the issue is the connector at the PCM or the PIN in the PCM. I can't test that. Either way, the issue is at the connection right there and I'm now leaning toward that connector on the end of the external harness.
Either way, the external harness is discontinued, so where can I get the connector on the end and fix just that?
Maybe I can spray some Deoxit in the end and see if whatever is not clamping down will loosen up...Not sure.
Every time I unplug the connector and plug it back in, I get no reading, or 5 degrees, or 150 degrees. The connector itself seems fine. Everything about this is screaming bad solder joint in the PCM. I have no other explanation for this.
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Fleet Mechanic
Joined: Aug 2005
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I can plug this in and get the proper reading of 72 degrees, and then 45 seconds later, it goes to -68.
Since the harness is discontinued, I can't test it, but it's either the connector or the PCM plug pin itself. I'll have to find someone with a PCM or the Pic N Pull that has them for 40 bucks and just buy that for testing purposes.
Definitely the downside to 'insisting' on keeping these old *** dinosaurs.
Since the harness is discontinued, I can't test it, but it's either the connector or the PCM plug pin itself. I'll have to find someone with a PCM or the Pic N Pull that has them for 40 bucks and just buy that for testing purposes.
Definitely the downside to 'insisting' on keeping these old *** dinosaurs.
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Thread Starter
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Fleet Mechanic
Joined: Aug 2005
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Likes: 29
Well, I guess I have to eat crow. Wiring issue it is. I've never seen it in 30 years but there is a first for everything. I went to the Pic N Pull and got a new transmission harness connector. Unfortunately, the transmission harnesses on everytruck had already been clipped and mangled. I could only get the connector and 18" of wire. However, I hooked up a working good temp sensor (clipped a connector for that too) into the harness and used that to plug into my truck PCM and the temp reads steady and solid. The connector of my old harness is bad. I do not know how to de pin the harness, otherwise I would.
How do you guys feel about cutting a harness with 23 wires and soldering on a new connector? I would rather not do this, but I don't have a lot of choice here since Ford in their infinite wisdom has discontinued the harness.
How do you guys feel about cutting a harness with 23 wires and soldering on a new connector? I would rather not do this, but I don't have a lot of choice here since Ford in their infinite wisdom has discontinued the harness.
Fleet Owner
Joined: Nov 2003
Posts: 27,916
Likes: 3,636
Thanks for posting what you have found, we were steering you that direction only because of experience saying what is "most likely" (never a sure thing)!
Anyway, there are several good videos on how to de-pin these connectors. I'll see what I have "bookmarked".
Anyway, there are several good videos on how to de-pin these connectors. I'll see what I have "bookmarked".
Thread Starter
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Fleet Mechanic
Joined: Aug 2005
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Likes: 29
these seem to be Tyco connectors but the videos I found don’t look like my connectors. Mine are far more robust and beefy. Lol.
Fleet Owner
Joined: Nov 2003
Posts: 27,916
Likes: 3,636
The transmission harness PCM connector:
2L1T-14A464-UC-011 Ford, OR
1-1438083-5 Tyco
30 pin, Key A
I believe that this is it (and it matches the connector shown in the adds for used harnesses):
https://www.connectorpeople.com/Conn...2L1T-14A464-UC
Maybe this harness would fit:
https://picclick.com/New-Oem-Engine-Trans-Wiring-2006-2007-Ford-F250-282291465619.html
https://www.ebay.com/itm/256712006844?fits=ake%3AFord%7Codel%3AF-550+Super+Duty&_trksid=p2332490.c101875.m1851&itmp rp=cksum%3A25671200684498ef2ab4d897418d918ac22dc8e caddf%7Cenc%3AAQAJAAABQNthdh9o32sOfKme0krmx3yc5y0D RWWwwpiraCEsA5rOcanQjqu91drTeDElZLF31uaWQXaQ2pNTl5 IMyA1OfooQwqEcJUvtG9LvKPKHgcRzphx12iPvBSva61o%252B MhuWL0pqOMbt%252BaoY3vep2vC5ANUYBSHys2TKzz1jhxJtqR E9Jr%252B%252BFO7W3kDdTHxL9gMsJa72ivfCT3zLGIjbuvyJ 9UGOssbDV%252B66FwHUkWEhfzKnH5zd8AkkxE1btX6I26ZA07 B9zdoOcX7JxuKgWFwgAziH4%252Bn%252F4fE3jQ2Nb1Xx4VxR LVXeKXJTdzxaZiiW3OuVQZGCPuIgsdtTO4TwIHzVTI69TwISsO k4xoAh131XbpEf6KmzRRm3sCQ6ksJ4fwQO0lBHl2EA%252FRq3 3Chyuo4cqqZeCOkV%252B1jQ4Po81dMKQVbq%7Campid%3APL_ CLK%7Cclp%3A2332490&itmmeta=01JCXT08PFKT83W31Q5ECW YFBE
2L1T-14A464-UC-011 Ford, OR
1-1438083-5 Tyco
30 pin, Key A
I believe that this is it (and it matches the connector shown in the adds for used harnesses):
https://www.connectorpeople.com/Conn...2L1T-14A464-UC
Maybe this harness would fit:
https://picclick.com/New-Oem-Engine-Trans-Wiring-2006-2007-Ford-F250-282291465619.html
https://www.ebay.com/itm/256712006844?fits=ake%3AFord%7Codel%3AF-550+Super+Duty&_trksid=p2332490.c101875.m1851&itmp rp=cksum%3A25671200684498ef2ab4d897418d918ac22dc8e caddf%7Cenc%3AAQAJAAABQNthdh9o32sOfKme0krmx3yc5y0D RWWwwpiraCEsA5rOcanQjqu91drTeDElZLF31uaWQXaQ2pNTl5 IMyA1OfooQwqEcJUvtG9LvKPKHgcRzphx12iPvBSva61o%252B MhuWL0pqOMbt%252BaoY3vep2vC5ANUYBSHys2TKzz1jhxJtqR E9Jr%252B%252BFO7W3kDdTHxL9gMsJa72ivfCT3zLGIjbuvyJ 9UGOssbDV%252B66FwHUkWEhfzKnH5zd8AkkxE1btX6I26ZA07 B9zdoOcX7JxuKgWFwgAziH4%252Bn%252F4fE3jQ2Nb1Xx4VxR LVXeKXJTdzxaZiiW3OuVQZGCPuIgsdtTO4TwIHzVTI69TwISsO k4xoAh131XbpEf6KmzRRm3sCQ6ksJ4fwQO0lBHl2EA%252FRq3 3Chyuo4cqqZeCOkV%252B1jQ4Po81dMKQVbq%7Campid%3APL_ CLK%7Cclp%3A2332490&itmmeta=01JCXT08PFKT83W31Q5ECW YFBE
Thread Starter
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Fleet Mechanic
Joined: Aug 2005
Posts: 1,689
Likes: 29
THIS DID NOT FIX THE PROBLEM. :/
I pulled both pins out of the connector. Put new pins with pigtail in the same locations and then touched the existing wiring.
NO TEMPERATURE READING!!!!!
So, the pins are not the issue.
I get a reading when nothing but the TFT is plugged into the PCM. When everything is plugged in as a whole plug, nothing.
So, I put new pins in the PCM Tyco connector and left the leads loose so I can test with them.
When these leads are hooked up to a free standing TFT sensor, I get a temperature reading. I can hook those wires up either way and it works.
When I use those leads to touch the existing harness wiring, I get no temperature reading when they are hooked up too the proper wires. If it flip the wires, I get a temperature readding.
This makes absolutely no sense to me. It's electrically impossible for a resistive sensor like this to operate in this manner.
Worst case, if I can't get it figured out today, I'll just tape the TFT to the firewall and hook directly into the PCM so the truck sees a positive and stable temperature and the dash lights will go out. Dash gauge is a dummy gauge and I don't particularly care what the temp of the trans is as long as there aren't any CEL.
I pulled both pins out of the connector. Put new pins with pigtail in the same locations and then touched the existing wiring.
NO TEMPERATURE READING!!!!!
So, the pins are not the issue.
I get a reading when nothing but the TFT is plugged into the PCM. When everything is plugged in as a whole plug, nothing.
So, I put new pins in the PCM Tyco connector and left the leads loose so I can test with them.
When these leads are hooked up to a free standing TFT sensor, I get a temperature reading. I can hook those wires up either way and it works.
When I use those leads to touch the existing harness wiring, I get no temperature reading when they are hooked up too the proper wires. If it flip the wires, I get a temperature readding.
This makes absolutely no sense to me. It's electrically impossible for a resistive sensor like this to operate in this manner.
Worst case, if I can't get it figured out today, I'll just tape the TFT to the firewall and hook directly into the PCM so the truck sees a positive and stable temperature and the dash lights will go out. Dash gauge is a dummy gauge and I don't particularly care what the temp of the trans is as long as there aren't any CEL.