2021 XLT cut out and fuel gauge issue

[railsandtrucks]

Thank you for all the advice and suggestions so far! Weather and work finally cooperated enough today for me to try taking a closer look at things myself this afternoon/evening.

I had a check engine light pop on again on me commuting back and forth (30 ish miles each way) the last two days. On the way home, I swung by autozone to pick up some electrical contact cleaner and to have the code read.

Code is P0463 - Fuel Level Sensor A circuit high.

Autozone also checked my battery, suggesting that a weaker battery could be a potential cause. Battery came back at 74% of charge, which does strike me as kinda low ?

After leaving Autozone, I swung by the car wash. Wanted to see if things would go berserk again - definitely caused some excitement, but the fuel gauge didn't move as much. The car wash though isn't as "new" as the one I went to while traveling, so maybe the underbody sprayer wasn't as advanced ?

Anywho, I crawled under the truck once I got home armed with WD 40, CRC electrical contact cleaner, some paper towel, and some grumbling. Found those two harness connectors right on the inside of the frame rail under the drivers side door as was suggested. I was able to pull them apart- didn't notice any gaskets though - is this normal ? Also, the one furthest rear looks like it had some corrosion or something on a few of the pins ? Light is kinda bad but hopefully it shows up.

I doused both male and female ends of the harnesses with WD 40, let it sit for a couple of minutes, then wiped down and shot with contact cleaner, also letting sit for a couple minutes. I then wiped both down, and re-connected, and let it sit for a couple minutes as well.

Came back around 5 minutes later and fired the truck up- initial start had the check engine light still on (I think I need to get the code cleared) but the fuel gauge went to normal (or at least, pretty close to where it should be, no other blind spot/cross traffic errors. I took the truck for a quick spin around the block, shut it down- no issues. Then re-started a few minutes later to back it up a little bit. At that point, the cross traffic alert errored out on me - so I don't think I'm completely out of the woods. Looking at the pictures now as I'm about to post them- those pins on the lower harness appear to have some garbage on them, and I'm wondering if that's the cause (or a symptom of a bad harness itself) ?

As always appreciate the input in troubleshooting this!

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[Toytec]

Without a doubt in my mind I believe you found the problem. Good work

 

[JDowns]

Looks like you isolated the issue.

The gunk you are noticing is burnt pins. I would venture a guess you have continuity across a pair of burnt pins.

There should certainly be a gasket in there, I can't imagine those harnesses not coming with a water tight seal gasket.

Not sure if that can be DIY repaired as it appears as though it cooked the plastic housing and you have burnt metal in there.

If there is enough slack the dealer may be able to repair the harness with a new end or new pins, or with a pin removal tool remove each pin and clean. But with a new truck I would want that fixed proper to avoid any long term issues. It sure looks like solder splatter in there where it cooked, so the issue is most likely buried deep in the harness.

@P. A. Schilke would have a good idea if those harnesses should have a gasket or not. I'd be shocked if they did not, otherwise forget any issues with alternators and water crossings, thats the main failure point.

 

[P. A. Schilke]

Looks like you isolated the issue.

The gunk you are noticing is burnt pins. I would venture a guess you have continuity across a pair of burnt pins.

There should certainly be a gasket in there, I can't imagine those harnesses not coming with a water tight seal gasket.

Not sure if that can be DIY repaired as it appears as though it cooked the plastic housing and you have burnt metal in there.

If there is enough slack the dealer may be able to repair the harness with a new end or new pins, or with a pin removal tool remove each pin and clean. But with a new truck I would want that fixed proper to avoid any long term issues. It sure looks like solder splatter in there where it cooked, so the issue is most likely buried deep in the harness.

@P. A. Schilke would have a good idea if those harnesses should have a gasket or not. I'd be shocked if they did not, otherwise forget any issues with alternators and water crossings, thats the main failure point.

Hi Jeff,

I have reached out to understand these new connectors as I do not know how the sealing is accomplished. What I learned it that the connectors are difficult for the assembly operators to solidly secure... Since the frame rail connectors go through salt baths etc, the sealing is good if properly connected but in this case it appears this was not the one to be fully seated. Conncetor changes from when I was at Ford and my own 2019 Ranger Electrical problems residing behind the left front headlight have given me pause for concern. When I did my wiring to allow me to flat tow my Ranger behind the RV, I inspected the connectors where I spliced the RV wiring and found everything nice and clean...not what is in the pictures. Wish I could help more but I am clueless on the sealing of current connectors.... I sense a change is coming as the current electrical integrity of Ford vehicles is questionable.

Best,
Phil

 

[JDowns]

Hi Jeff,

I have reached out to understand these new connectors as I do not know how the sealing is accomplished. What I learned it that the connectors are difficult for the assembly operators to solidly secure... Since the frame rail connectors go through salt baths etc, the sealing is good if properly connected but in this case it appears this was not the one to be fully seated. Conncetor changes from when I was at Ford and my own 2019 Ranger Electrical problems residing behind the left front headlight have given me pause for concern. When I did my wiring to allow me to flat tow my Ranger behind the RV, I inspected the connectors where I spliced the RV wiring and found everything nice and clean...not what is in the pictures. Wish I could help more but I am clueless on the sealing of current connectors.... I sense a change is coming as the current electrical integrity of Ford vehicles is questionable.

Best,
Phil

Phil,

If there isn't a surround gasket then I would tend to believe that the male side is hard plastic as shown, and the female mating side is probably a softer plastic that creates the seal when properly latched.

From the photo if the top left was pin 0.

Pins 4 & 7 look cooked, with pin 7 being the major concern, the blue and orange tint is a dead give away something shorted out.

I'm betting the black material is actually burnt plastic from the female side, possible the seal material being a softer plastic.

To the OP; hopefully they can repair that quickly for you. If it were me I'd want a new harness. No telling what damage was done to the wires that you can't see since that wire had to get pretty hot for the blue and orange burn marks on pin 7. Best of luck and sorry to see this happen.

 

[JesseS]

The male side of that plug is supposed to have a rubber gasket around it, looks like a double finned rubber lip, sometimes red or orange, I don't see it in this one. So either it was never there and mosture got in causing corrosion or the contacts were not fully engauged to start with and the higher electrical potential caused heat. Take it to the dealer and show him, he will need to order a new harness.

 

[P. A. Schilke]

Phil,

If there isn't a surround gasket then I would tend to believe that the male side is hard plastic as shown, and the female mating side is probably a softer plastic that creates the seal when properly latched.

From the photo if the top left was pin 0.

Pins 4 & 7 look cooked, with pin 7 being the major concern, the blue and orange tint is a dead give away something shorted out.

I'm betting the black material is actually burnt plastic from the female side, possible the seal material being a softer plastic.

To the OP; hopefully they can repair that quickly for you. If it were me I'd want a new harness. No telling what damage was done to the wires that you can't see since that wire had to get pretty hot for the blue and orange burn marks on pin 7. Best of luck and sorry to see this happen.

Hi Jeff,

I am amazed that there was enough current passing through these wires to burn them without a fuse blowing but the electrical system in its entirety is not clear to me... I think he is a victim of an improperly seated connector and the dealer should address the problem and hopefully OP will file a complaint with Ford Customer Care.... Gotta put a nail in the coffin of this electrical system JMO!

Best,
Phil

 

[9zero1790]

wow! i hope this is an isolated thing. great job finding it ! when I was looking at the photos it almost looked like fire ants in the plug, had too zoom in to see it was not lol.

 

[Jason B]

Good on you to find the problem. But this is not a DIY repair. This is a manufacture defect that needs to be corrected by Ford. And I wouldn't settle for a splice in new connector which may lead to future problems at the splice. It will take a while, but Ford needs to replace those sections of the harness, both sides.

 

[railsandtrucks]

Good Morning! Quick update, and apologies for the delay. I swung by the dealership over a week ago where I purchased the truck, and got an appointment in for this coming thursday (appointments were two weeks out).

Before setting up the appointment I talked to my sales guy real quick (he's a car guy) to get his thoughts on how much I should reveal to service to make sure I don't run into any warranty issues. A quick chat with his boss and got the greenlight to give service the full rundown.

The issue definitely gets worse when it's wet, and when the fuel tank isn't nearly completely full - when full the fuel gauge will sometimes work, and I don't lose the back end safety features of the truck (cross traffic, backup, blind spot) - as soon as it gets either wet or the fuel tank drops below about 3/4, I have more consistent issues though the fuel gauge is hit/miss regardless.

Wish me luck this coming week!

 

[JDowns]

Hi Jeff,

I am amazed that there was enough current passing through these wires to burn them without a fuse blowing but the electrical system in its entirety is not clear to me... I think he is a victim of an improperly seated connector and the dealer should address the problem and hopefully OP will file a complaint with Ford Customer Care.... Gotta put a nail in the coffin of this electrical system JMO!

Best,
Phil

I wouldn't be surprised if the signal wires are non fused as there would be no expectation for a large current draw. The addition of salt creep into the housing (increased conductivity), multiple power leads, small gauge signal wire, and most likely a hardened PCB design on whatever module is driving the components at the rear of the vehicle, it wouldn't take much amperage to cook the tin connector pins. My hats off to whoever designed the PCB module, the failure cooked the pins and the plastic with no apparent harm to the module(s) itself.

Good Morning! Quick update, and apologies for the delay. I swung by the dealership over a week ago where I purchased the truck, and got an appointment in for this coming thursday (appointments were two weeks out).

Before setting up the appointment I talked to my sales guy real quick (he's a car guy) to get his thoughts on how much I should reveal to service to make sure I don't run into any warranty issues. A quick chat with his boss and got the greenlight to give service the full rundown.

The issue definitely gets worse when it's wet, and when the fuel tank isn't nearly completely full - when full the fuel gauge will sometimes work, and I don't lose the back end safety features of the truck (cross traffic, backup, blind spot) - as soon as it gets either wet or the fuel tank drops below about 3/4, I have more consistent issues though the fuel gauge is hit/miss regardless.

Wish me luck this coming week!

Glad to see the dealer taking care of you. It's always nice to have a good relationship with your sales and service departments.

My thoughts and speculation on why the erratic behavior when the fuel tank drops below a specific volume. The fuel gauge sensor is some type of analog signal (0-10VDC, 4-20mA, etc). Full tank levels could represent low voltage and empty tank higher voltage. As more voltage is being sent through the wires when the tank gets lower, the signal wires are being corrupted with additional voltage/current at the harness causing the erratic behavior.

 

[Mr.Scary]

It could be something simple like a lose ground wire. Had the same problem on an old zx3 I had years ago

 

[Marpater]

My thoughts and speculation on why the erratic behavior when the fuel tank drops below a specific volume. The fuel gauge sensor is some type of analog signal (0-10VDC, 4-20mA, etc). Full tank levels could represent low voltage and empty tank higher voltage. As more voltage is being sent through the wires when the tank gets lower, the signal wires are being corrupted with additional voltage/current at the harness causing the erratic behavior.

This makes perfect sense as when the issue first was noticed the fuel gauge went to reading empty (failsafe empty?) = max signal V or A.

 

[railsandtrucks]

Hey everyone! Have some good news to report! Got my truck back from service this evening and so far so good with the short drive back to the house. Supposed to be kinda cold and rainy tonight, so tomorrow morning's drive into work should be a good test - I'll probably dip below half a tank on the drive in tomorrow as well.

Dealership did a good job keeping me in the loop and I'm cautiously hopeful and optimistic they got it all sorted out. First thing they replaced were the connectors that you all helped guide me too, but after that apparently that wasn't the only issue.

They also have listed that after that was done "SODL failed to communicate to network. Inspected all connectors dealing with SODL. Found connector C4471 to have water in connector" So they got that squared away as well and apparently after that the codes cleared and the truck behaved like normal.

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