CEL lit up yesterday. Had 2 codes: p0463 (fuel level sensor A high) & p0720 (Output speed sensor).

The truck is running fine as far as I can tell. The fuel gauge has gone wonky once or twice (drops to empty, then back to correct level).

From what I can tell the output speed sensor is a <$20 part and goes in the side of the tranny. Easy enough.

The fuel level sensor is part of the sending unit? So I'd drop the tank to get that out?

I'm curious if the fact that they both showed up at the same time could indicate anything else, or is it just coincidence?

Thanks!

 

Probably just coincidence.

Check connections back at the tank, make sure everything is clean, and tight. Follow the harness forward, make sure it hasn't gotten pinched/worn anywhere along the way.

Replace the sensor in the trans.

 

there were some old posts a long time ago that recomended a regular gas treatment with chevron/techron to clean the in-tank sending unit. that stuff's pretty expensive, but i use a bottle about once every 3-6 months just for good measure.

i think? the sending unit is integrated with the fuel pump? so its expensive as hell.

 

Ooooh, got underneath the truck to peek at things and found that one of the straps holding the gas tank had rusted through and let go!

Guess I'll take care of that 1st.

 

To conclude this thread, I put new straps on the gas tank so it wasn't hanging at an angle. That seemed to clear up the p0463 code.

Put in a new output speed sensor and that code seemed to clear up as well. Some other shifting irregularities I'd experienced were gone once this was replaced too.