Ford TSB 06-2-12 covers this. Let's see if I can do it in a couple replies...
MIL ON WITH PCM DTC P0463 AND/OR IC DTC
B1201 - FUEL GAUGE DROPS TO EMPTY OR SLOW
TO UPDATE AFTER REFUELING
This article supersedes TSB 05-21-3 to update the Service Procedure.
Some 2002-2006 Explorer/Mountaineer and 2003-2005 Aviator vehicles may exhibit a customer complaint of the fuel gauge being slow to read full after refueling, the malfunction indicator lamp (MIL) on with diagnostic trouble code (DTC) P0463, instrument cluster DTC B1201, and/or the fuel gauge dropping to empty. This may be due to the fuel level sender assembly sending incorrect data to the instrument cluster and/or powertrain control module (PCM).
Refer to the following General Information for a description of two (2) modes of fuel gauge operation prior to following the TSB Service Procedure. This brief explanation of current fuel gauge strategy will help ensure the correct diagnosis is made. The fuel gauge on these vehicles has several distinct modes of operation. The difference in the various modes is the speed at which the fuel gauge pointer moves in relationship to fuel level input from the fuel level sender. After reviewing the General Information, refer to the TSB Service Procedure.
Fuel gauge strategy provides several modes of operation. One being referred to as Fast Acquire Mode and another as Slosh Mode. The time for the fuel gauge pointer to move from "E" to "F" can be 2 seconds, 17 minutes or 55 minutes depending on build date and which mode the fuel gauge is in.
Fast Acquire Mode:
The 2-second "E" to "F" mode is referred to as Fast Acquire Mode. Fast Acquire Mode strategy requires two (2) conditions to be met before the fuel gauge indications can be updated. First, at least four (4) gallons of fuel must be added to the fuel tank. Second, the Instrument Cluster must acquire a valid Key-ON fuel sender reading within 1 second of the key being put in the Run position. The Key-ON sample reading is considered valid if the fuel sender reading is between 10 and 160 ohms. If both of these conditions are not met, the fuel gauge stays in Slosh mode. If the Cluster does not go into Fast Acquire Mode after a refueling event, the system will stay in Slosh Mode. This will result in a slow to Read Full event.
The 55-minute "E" to "F" mode is referred to as Slosh Mode. In Slosh Mode, this is 55 accumulated minutes of the key in the Run position. Unless the conditions are met to put the fuel gauge into one of the other operating modes, the default is Slosh Mode. Example: If a customer operates their vehicle 11 minutes per day, it will take 5 days to accumulate 55 minutes of run time. This means it will take 5 days for the fuel gauge to go from "E" to "F".
NOTE SLOSH MOD[ STRATEGY WAS REDUCED FROM 55 MINUTES TO 17 MINUTES FOR VEHICLES BUILT AFTER 12/22/2004.
NOTE IT IS IMPORTANT TO THOROUGHLY UNDERSTAND THE CUSTOMER CONDITION BEING REPORTED.
It is important to determine if the customer has a fuel gauge that slowly gets to full or has a fuel gauge that never gets to "F" (stuck) when the fuel tank is filled. If the fuel gauge slowly goes from "E" to "F" (in 55 minutes of key in the Run position or less), the problem is most likely not in the cluster. It is absolutely imperative that the appropriate pinpoint test(s), located in the Workshop Manual or this TSB, be completed for this customer complaint to determine root cause of the condition. Root causes may include but are not limited to: the Fuel Sender, Fuel Tank, Wiring, or Instrument Cluster
WARRANTY STATUS: Eligible Under Provisions Of New Vehicle Limited Warranty Coverage
BASIC PART NO. CODE
Initial Steps (All Vehicles)
1. Retrieve and record PCM and the instrument cluster (IC) DTCs, from continuous and on-demand self tests.
2. If DTCs other than B1201 or P0463 are retrieved, follow normal Workshop Manual diagnostics, DO NOT CONTINUE WITH THIS TSB.
3. If IC DTC B1201 and/or PCM DTC P0463 are retrieved, perform Procedure A for 2002-2005 Model Years and Procedure B for 2006 Model Years.
4. If No DTCs are retrieved, go to Procedure C.
PROCEDURE A (2002-2005 MY)
CHECKING FUEL GAUGE OPERATION:
NOTE WHEN PERFORMING STEPS 4A-0, FUEL GAUGE SLOSH STRATEGY REQUIRES SPECIFIC KEY ON AND KEY OFF CYCLE TIMES. THESE TIMES MUST BE OBSERVED OR THE DIAGNOSTIC RESULTS WILL NOT BE ACCURATE.
1. Key in OFF position.
2. Remove Fuse F1.15 (15 amp) from the Battery Junction Box, wait 1 minute and reinstall fuse.
NOTE THIS IS DONE TO RESET THE CLUSTER FUEL GAUGE TIMERS. FAILURE TO COMPLETE THIS STEP MAY RESULT IN ERRONEOUS TEST RESULTS.
3. Disconnect the in-line connector to the fuel pump module (C438 for 4.6L) or (C431 for 4.0L), located on the RH frame rail.
4. On the vehicle harness side of the connector, connect one lead of an instrument gauge system tester (Rotunda # 014-R1063 or equivalent) to Circuit 1356 (LG/VT - Pin-8 in Connector C438 and C431) and the other lead to Circuit 1357 (LB/YE - Pin-5 in C438 for 4.6L or Pin-4 in C431 for 4.0L) (Figure 1).
a. With the key in the RUN position, move the shift lever from PARK to DRIVE, wait 10 seconds and then back to PARK.
b. Wait 30 seconds with the key in the RUN position and the shift lever in PARK.
c. Turn key to the OFF position.
d. Set the tester to 160 ohms.
e. Turn key to the RUN position, move the shift lever from PARK to DRIVE, wait 10 seconds and then move the shift lever back to PARK.
f. Wait 30 seconds with the key in the RUN position and the shift lever in PARK.
g. Turn key to OFF position and wait 30 seconds.
h. Set the tester to 15 ohms.
i. Turn key to RUN position, move the shift lever from PARK to DRIVE, wait 10 seconds and then move the shift lever back to PARK.
j. Wait 30 seconds with the key in the RUN Position and the shift lever in PARK.
NOTE THE FUEL GAUGE SHOULD READ "E" (EMPTY MARK) OR BELOW WHEN CARRYING OUT THIS TEST STEP.
k. Turn key to OFF position and wait 30 seconds.
l. Set the tester to 160 ohms.
m. Turn key to ON position.
NOTE THE FUEL GAUGE SHOULD READ "F" (FULL) OR ABOVE WHEN CARRYING OUT THIS TEST STEP.
n. Wait 1 minute for the gauge to respond.
o. Turn key to OFF position. After completing Steps 4A-0, if the fuel gauge operates correctly replace the fuel sender only (9A299). If not, refer to the Workshop Manual, Section 413-01 and perform normal diagnostics.