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Oct 2, 2020 | 02:35 PM

IHateCommieCars

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From: Houston, Texas

Next problem

Made it back home. Truck has been driving fine. Dropping off my last shipment today, thinking how great this truck was.

I still can that little hiccup going into 3rd gear, so with an empty trailer, I tried driving in tow/haul mode for a few miles, but stayed the same. Turned TH back off. Cruising down the freeway a few miles later, I feel a jerk, my transmission drops out of overdrive, and the trans light starts blinking.

Pull over asap stop at a light and it drives away fine. Find an empty lot to pull in. That's where I'm at now.

I get codes p0657 and 0962. Cleared them and they come right back.

This has brand new transmission harnesses inside and out. There is still an upper harness from the bell housing to the PCM/TCM? that is old.

Any other ideas? I tried to drive again and now it doesnt want to move.

Oct 2, 2020 | 02:54 PM

TooManyToys.

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https://www.ford-trucks.com/forums/1...rans-help.html

Its also been mentioned to be a faulted PCM issue, but I'll the rest to Mark. Well, one of the Marks.

Oct 2, 2020 | 05:20 PM

IHateCommieCars

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Thanks. I did get it to drive and made it home. Apparently, I only have one forward gear, I think it's 5th.

I recall you kinda side-eyed my first posts on this, Jack, when I found the shorted out lower trans harness and asked what could have made them short out, lol. You had to know I'd be back again.

I hope it's just the upper harness. Checked locally and there's not one at any of the dealers. I'd have to wait 3 days. So, looks like I'm cannibalizing the ambulance again. Not sure how much work it will be getting to the PCM - I can't see it from the front or back of the compartment, but nothing I can't screw up, lol.

If it's easy to get to, could I swap out the PCM too? Or does that require re-flashing or other interface issues?

Oct 2, 2020 | 05:38 PM

IHateCommieCars

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This bus seems to have a love/hate thing for me. When it's running, with AC or not hot outside, it's perfect for what I do. Clunky and noisy driving around town, but once it's cruising on the highway, it's smooth. Provides a comfy RV-function so I can lay over a few days and wait for a good-paying shipment. Can't do that sitting in my truck, so I was either paying for hotels and taking the first lousy load I could find to get back home. I could literally live out of this bus a month or two at a time, collecting money as I drive around. But, every time I start thinking about how nice it's going to be, the bus hates on me.

Oct 2, 2020 | 05:39 PM

TooManyToys.

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PCM replacement requires an identical vehicle or a reflash. If it comes to a PCM, there are companies that repair them and reflash before sending back.

I go through this with transmission Mark before I'd do anything more than a new harness.

A wire can rub through and short on its own. But when there is no evidence of rub through against and object or internal within the harness, then it's usually a short from a component.

Oct 2, 2020 | 08:18 PM

IHateCommieCars

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I'm going to PM Mark. In the morning, I'm going to swap over that harness. It looks pretty easy, just one more connector from the PCM to the lower trans harness, and that one's easy to get to. Just looks like getting to the PCM is the hard part, buried in the engine compartment.

I need to look up my old posts, but I'm pretty sure these are new codes. The initial issues produced codes pointing to the intermediate speed sensor on the trans. Mark suggested harness, and sure enough, the harness was obviously shorted right at the ISS connector. New harness, seemed to fix it, but broke the internal harness connector getting it off. Sure enough, a thousand miles or so and the TCEL comes on again, with different codes pointing to the position sensor inside the pan. Replace that harness/broken connector and the problem goes away again. Drive 2500 miles, and now the TCEL comes back again, with, I'm pretty sure, different codes.

It could be components in the transmission - actuators, sensors, etc. - or maybe the PCM component, but gosh, it sure seems like it should be the upper harness.

Oct 3, 2020 | 05:55 PM

IHateCommieCars

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OK, Mark agreed that it was probably that last section of harness, and the PCM if not. So I pulled it this morning, tore into half of it that looked beat up a bit. Found some wires stuck together, but none burned through or signs of heating. When I pulled them apart, some bare wire showed, so I taped it up and plugged it back into the truck. No change. So I pulled the harness out of my ambulance. It didn't look much better, but it fixed the problem. Truck is running fine, although it prolly still has the 0404 and glow plug codes. But no CEL.

Leaving for LA in the morning.