Hey everybody, new member, first post. I recently purchased a 2006 Lariat 2WD. Everything's fine, but the fuel gauge acts strange. Upon filling the tank, the gauge went to below E, and the low fuel warning message came on about every 10 mins. while driving. After about 90 mi., next time the truck was started, the fuel gauge went to F, and seemed to track usage pretty well, although the reading was obviously high. I've filled up three times, same result. I read through some of the posts about checking the DTC readouts in the test function, and the readings seem to match what I know is in the tank. Does this sound like a problem with the gauge itself, rather than the sending unit, and can you replace the fuel gauge independently of the entire instrument cluster?
In addition, during the test function, I get a reading of a diagnostic trouble code 9201. Any ideas would be appreciated.

 

Fuel sender circuit issue is what that code shows up as. If I am not mistaken, the sender unit is a part of the fuel pump.

 

So I'm looking at replacing the fuel pump?

 

Usually yes that is the case. It is located in the fuel tank. If anyone else can chime in, it'd be appreciated.

 

Well this is gonna sound whacky and I understand that but mine does the same thing if I leave the keys in the ignition while filling the tank. If I leave them on the console, no issues. You might consider removing one of the battery cables to reset the PCM and put the keys in yer pocket when filling. Shouldn't make any difference but I can guarantee you if I leave the keys in the ignition while filling it the gauge won't work right. Must be gremlins....

 

Interesting. Don't think I've left the keys in the ignition while filling the tank - I usually don't get out without them - but I'll try the disconnect thing. I guess it couldn't hurt. Thanks.

 

My 06 f150 4x4 lariat did the same thing, was told it was from cheap junk cutrate fuel. Also told there was a tsb from ford on this , never verified that. Cheap fuel and high sulfer content supposed to be the blame. The sulfer builds up on the sending unit and causes wacky reads. I was told to run a couple bottles of techron fuel additive to clean the system. In short it worked. The first bottle I used a large bottle to about a 1/4 tank of gas then added 5 gal to mix. 2nd bottle again the large to a tank of gas. was also told if you live where there is a Sunoco run there gas supposed to clean the same. This is what I was told,it worked ,so far, just my 2 cents. Also since, I have ran a small bottle , I time it to every oil change since.

 

My 07 f150 xlt did this too, especially during the winter here in the northeast. A few weeks ago i replaced the FPDM due to a missfire and a hard start, and since than the fuel gauge has been fine.

Drop your spare tire and check to see what the condition of your FPDM is(most likely if you haven't replaced it, its the corroded box on a cross beam with a large crack in it)
there is a ton on info/pictures on the forums here that show the corroded unit with cracks/covers missing.

My guess is if any moisture gets up into the unit, it can cause a short, which in turn could cause the circuit to send a wrong signal to the dash...

 

My fuel gauge has been a little funky lately...

Sometimes after parking in my driveway it shows way higher than it was before parking (driveway is an uphill slant)...but takes about a day to correct itself...

It will also read slow for about the first 1/2 tank (get about 200 miles on first 1/2, but 100 on last half). I get real excited t see that 200 miles, thinking maybe, just maybe I can squeeze out 350+ miles on a tank...

Fuel pump & sender was replaced at 51k (6/2008)...hit 156k today

 

Yeah, if you leave the ignition on so the fuel gauge is reading while filling, then it confuses things. After a while it will recalibrate itself.

 

I just bought a 2006 F-150 that didn't have a working fuel gauge for at least three years. Previous owner (a friend) was quoted $1200.00 to fix. I spent a few days freeing up the bed bolts with heat underneath at the nuts and welding nuts to the TP45 bolts. (I cut off the nuts and ground everything back smooth)
Once I got the bed off I was able to check the sending unit. I removed it, tested it with a multi-meter and found it to be perfect. Since I am a high school auto teacher I had some time when I removed the sender so I bench tested it. We found 150ohm resistance at full and about 10ohm at empty. (don’t quote me on the numbers, I was only looking for scale movement).
I then started tracing the wires for the fuel sender. The two wires I was looking at were the Yellow with White stripe and Black with Orange Stripe at the four wire connector at the sender/pump unit.
I found a broken red wire near a black box about 1.5” X 3/4” X1/4”. This box had five wires;
1) the broken red wire
2) the yellow/white from the tank unit
3) the black/orange from the tank unit
4) the yellow/white to the gauge
5) the black/orange to the gauge

I downloaded a wire schematic and it shows a FLEX FUEL AC/DC converter in the wire system. I studied it and decided to cut out this black box and wire the two corresponding wires together. ie: yellow/white to yellow/white and black/orange to black/orange.
I then cut out the red wire and taped it up.
This cured my issue. I now have a functioning fuel gauge and it cost me $0000.00 dollars.
I immediately told my friend, the previous owner, and rubbed it in. ☺

 

This may sound whacky but this does nothing for me. I put my keys on top of the bed above the gas cap while filing. It changes nothing for me.

The only time I have a problem is when I run the fuel below the "50 miles to empty" when you start getting the warning of "LOW FUEL". Once this happens and I then fill up you usually have to start and run the truck 2-3 times before the fuel gauge returns to normal. The first time I start it up after filling it may still show low (1/8 tank or less) and I may still get the LOW FUEL warning even though I know I have a full tank. Later I can get back in the truck and start and it might show about half tank. After the second or third time it may go back to normal.

But..... it all just seems weird and is only an issue when I run below the 50 mile to empty mark and get the LOW FUEL warning. Any other time I don't have an issue.

As long I stay above the 50 miles to empty mark and I don't get a LOW FUEL warning..... I don't have any problem with the fuel gauge operating properly.

Again, having keys in or out of the ignition or cab has done nothing for me.

 

My fuel gauge went all over the board once, I had just filled up one day and it said 1/4 tank. Later on it said 1/2, then 1/8. The fix, the sending unit was indeed bad ( Dealership's claim ). The bill was $380 fixed and done. There is no need to pull the bed and it did not cost $1200 to fix. So....

 

The sending unit is a very simple one-contact variable resistor. Easy to repair and clean.

 

Hi, this is my first time posting anything. I had the exact same problem as jdinner and I did exactly what he did and now my gauge went from always reading empty to always reading full. Can any one tell me why that would be. Thank you.