I was checking some of the items in the dash diagnostic test when the “trip” button is held for 3 seconds.

I noticed that the Fuel Indication System was showing a big difference between the F1 and F2:

F1 209
F2 073
FP1 218
FP2 020
FPt 123

Do you guys have any thoughts about this? I would think that the readings should be similar.

Not sure what FPT is. Possibly total.


thanks

 

Max, F1 and F2 are the fuel levels in the 2 halves of the gas tank. So, having a difference between the two is more a function of which way you too your last hard turn and where the gas splashed too. F1 should normally be higher as this is the side of the tank that feeds the engine. the other side is there just ot have volume in the tank.

Now, FP1 and FP2 are filtered versions of F1 and F2. So, these numbers should be very close (as they are in your case) to its mate, but the FP value will move much slower as it is averaging out a number of F values.

Kinda like FPT is the average of the FP values and this is the value that gets sent to the instrument cluster to indicate how much fuel is in the car.

So, you can use these different values to do some troubleshooting. The F values are from the sensor. The FP values are those from the ECU, and the FPT is the value leaving the ECU to go to the instrument cluster. You get a disparity in your fuel level system, you can use these numbers to get an idea of where the problem lies without having to crawl under the car.

 

Thank you for the explanation. Much appreciated.