possible wiring but most common fault was the fuel GAUGE on the gas tank itself DTE wont work if it doesn't know how much fuel your using......if you replace fuel gauge set indicator to about half way with a magnet before you install ....also plug in/ ignition on and check fuel gauge to check if reading ok...
Note - only undo 2 small screws holding gauge in
DTE is a calculation of how much fuel you have and driving habit ie.drive hard and DTE reading will be lower than driving like granny for same amount of fuel......