I have a 2002 Lincoln Navigator. i recently seen my Trip Computer goes out of sink all the time now. It will show under Average MPG it will show 99.99 and under Miles to Empty on a full tank it will read 800 miles till empty. Has anyone experience this? Also to reset it , i would have to disconnect battery to have it work for a while than it will go back the same.





Full Tank of GAS





Average Mile per GAL





Miles to Empty Tank

 

If my Expedition was getting 99.9 mpg, the last thing I would do is try and fix it.

 

Sounds like the kind of car that would have men in black suburbans from the evil petroleum industry pay you a visit.. haha.

But on a more serious note, do you have any way of connecting a scanner to it and see if there's any codes? Even if there's no CEL, there may still be codes in there indicating what might be wrong, at least a pointer. Would also be helpful to see the live data from the ECM on different things to see what it's doing.

 

ROTFLMAO

 

Does it only do this with a full tank?
Have you tried resetting the unit?

 

Only if it was true, I would not care either.

 

no it will do this at any level of fuel.
I have tried to reset the trip computer back to 00.00 under AvG RPM but it will jump back to 99.99

It will only work properly after resetting the trucks computer by disconnecting the battery. This is temporary fix until it acts up again.

 

Yes I do have a scanner. I have tried to see if any codes where showing but to no.

I will do a full scan later today and post results .

 

Okay, last question...
When it jumps to 99.9 MPG etc., does the fuel gauge on the dash jump up as well?

 

No, fuel Guage on dash works perfect.

 

Is the check engine lamp on @ KOER?

 

In that case the overhead module is bad, check eBay for a replacement.

 

thanks alloro, just disconnected the trip overhead computer without disccounting the battery. the trip computer did reset it self and work for a bit and went back to the problem i was experiencing. i will purchase a another one.

 

If they're cheap, go for it. If not, and you're confident with electronics, you could try to disassemble it and find out what is wrong with it. Could be a simple solder joint or something like that which makes the readings freak out. It might also be a signal that is shorted, not sure how these read the data from the ECM, haven't looked at the wiring diagram from them yet.

 

One could also try the oven trick, it once saved me from having to replace a laptop motherboard.