2017 Low Fuel Light Issues.

Keith Browning · September 27, 2017

I recently had a 2017 6.2L in with a fuel gauge accuracy and distance to empty that was way off issue that was corrected by TSB 17-0046 by replacing the fuel tank and sender. But today I had two 2017 F550 ambulances ready for delivery to the FDNY that had 1/2 tank of fuel or more and the low fuel light was on. The distance to empty on both was about 60 miles. I thought this might be a similar issue to I looked the tank over really good and found no damage. No code anywhere and of course they passed all testing. THese rigs spent the last several moths being moved around the upfitter's lots, idle to hell and driven a little. The average MPG was in the mid 5's on both trucks. Turns out that when this happens the fuel calculations which are a 300 mile running average will give you these numbers and cause this condition. Perfectly normal but not acceptable to a customer.

TO correct such an issue you need to reset the modules according to the Hot-Line. Disconnect all batteries for 5 minutes then touch the negative and positive battery cables together for 30 seconds. Then restore all connections. THis will effectively reset the MPG to the default 18 MPG and as a result return the DTE to a more realistic number as well as turn off the low fuel light. The light is not triggered by the actual fuel gauge but the a calculation of that and the average MPG. that determines the DTE which for normal keys is 60 miles.

Keep that one in the back of your minds.

forddieseldoctor · September 28, 2017

We have a local hotel that has a F-550 cube truck that only reads 150 miles to e with a full tank because it doesn't go far and idles forever. Thankfully it's a gas in it.

tonybullitt · September 28, 2017

Thanks, that's good to know.

jimmy57 · September 28, 2017

Is the part where someone needs to say liars figure and figures lie?

These days so many vehicles only use the tank sending unit for specific level sampling and other ranges the PCM consumption info is the basis for fuel level on gauge. Not so much for regular shaped truck tanks but very common on all those tanks that fill up all manner of irregular shaped space under back seat.