2007 gas gauge problem: not moving to full?

I believe your dealer is correct.

 

I don't think you have to put as much as 4 gallons in. However, it is more than 2.5 gallons. It's in your Owner's Manual. Just drive until you get down to 2 pips and fuel again. The 'guess' gauge will correct itself with that fueling.

 

Wow! You picked the only one honest dealer out of five. What was the trick?

 

2.5 gallons isn't enough to initially reset the 'guess gauge". It will probably read full after several starts.

 

I just had the same problem for the first time with my 2007 Touring. Was down to four pips, went to the station and filled with over 4 gallons. The pips didn't move. I drove around the block and back to the station. The attendant, who has filled my car hundreds of times, assured me that he put gas in the car. He tried to put more gas in but couldn't as the pump shut off. (Luckily it didn't overflow.)

The pips still haven't moved. It sucks to fill your tank and not even have the pleasure of knowing that you did it. Will check it out in the morning to see if the gas registered.

 

If your tank is full and the gauge is not showing full, then you may need to have the inclinometer reset. You can do it yourself or have the dealer do it.

 

Thanks EZW1. Does the manual or some other source explain this this?

 

I'm taking this directly from the Prius ME maintenance manual:​

Start with a full fuel tank (top off is best that way there's no guessing whether it's full). Then park the vehicle on a level surface and let sit for 5 minutes before you continue.

For the purpose of correcting the calculation of the
fuel level by the meter ECU, 2 inclination sensors that
detect the vehicle's longitudinal and latitudinal
inclinations are installed in the meter ECU. The fuel
temperature sensor are installed in the fuel tank to
detect the temperature in the fuel tank.
• The fuel level is calculated by the meter ECU in
accordance with the signals of the sender gauge
located in the sub tank and the vehicle speed signal
received from the brake ECU. At this time, corrections
are made by the signals from the inclination sensor
that detect the vehicle's longitudinal and latitudinal
inclinations and the fuel temperature sensors that
detects the temperature in the fuel tank. For the
inclination sensor centered value setting, refer to the​

following procedure:

Perform the following procedures to correct inclination of
the meter and inclination sensors when installing /
removing / replacing the meter or after replacing the
inclination sensors or main base.

(a) Setting procedure
(1) Connect the connector and install the meter
securely in the position shown in the illustration
so that it is inclined at a 20 degree angle to the
vehicle's vertical line A.
(2) Park the vehicle on a level surface.
(3) Turn the power switch ON (IG).
(4) Set the odometer display into the "TRIP A"
mode.
(5) Turn the power switch OFF.
(6) Press and hold the ODO/TRIP switch while
pressing the power switch twice ON (IG). (Do
not put your foot on the brake.)
(7) Press the ODO/TRIP button (switch?) 3 times
within 5 seconds and hold it at least 5 seconds
until the Inclination Sensor Information is
displayed on the odometer.
(8) Release the ODO/TRIP switch.
(9) Press and hold the ODO/TRIP switch for at
least 5 seconds to update the centered value.
The third digit will indicate the status. The value
of "1" indicates a successful reset.
HINT:
• If "0", "2", or "3" is displayed, perform the
procedure "Turn the power switch ON (IG)"
again.
• Once the reset is complete, the odometer
will returns to normal.
(10) Release the ODO/TRIP button. (Once the reset
is complete, the odometer will returns to
normal.)​

Hope this helps you.​

 

Thanks so much for taking the time to track this down for me.

 

After driving about 40 miles this morning, the gauge finally caught up with the filling and went to 10 pips.