OH Readout just went goofy......

[ERohloff]

Recently bought a new 3500. So far it's been better than expected. MPG is great and also better than expected.



Problem: For the first 1000 miles the overhead was reading 18-20 with easy driving. Hand calc's confirmed this great milage. DTE worked well also agreeing basically with the amt of fuel in the tank.

BUT at about 1200 miles the OH reads consistently in the 8-11 range and seems to jump all over. On harder driving or up long grades the OH MPG creeps up (not down) and visa versa on down hill runs ( numbers go down instead of up). Does opposite of what it should be doing. AND the DTE is now screwed up also. Sits at 994, then jumps to 545 and flips all around.

Truck now has 1800 miles.



Pretty sure it's the OH and not the actual MPG that changed as the last hand calc'ed tank (Liquid to the brim each time) was 21. 8 mpg. (Steady 60 mph, two lane roads).



Question 1: Going to see the dealer next week but thought would get some input here first... ..... Has anyone here had this problem? OH worked well, then went goofy. How fixed?



Question 2: Can the OH be reflashed to correct or does the main CPU need to be reflashed to try to correct. I am very hesitant to let the dealer reflash the main CPU as I don't want to screw up the great MPG I'm getting just to correct the OH readout issue.



Any input appreciated... ...

bob r...

 

[DBond]

Check if you are in metric mode. The US/M button toggles between the two.



In metric fuel economy is in Liters/ 100km.



toggling my present 18. 5 mpg to 12. 7 L/100km

 

[Cattletrkr]

What are the odds if it is the US/M button that we'll ever read about it??? :-laf

 

[JHardwick]

What are the odds if it is the US/M button that we'll ever read about it??? :-laf

That was actually a pretty good call by DBond, I'd never have thought of it.

 

[ERohloff]

DBond, Good call !!! It was in metric mode. Did read 11. 4 and with a flip of the mode button it now reads 20. 5mpg. More in line with what I'm hand calculating.

You'd think after being on this earth for 60 some odd years this new Dodge owner would have caught that... ... ... And thanks for saving me the embarrassment of having the dealer show me the mode button face to face.

Still doesn't explain why the DTE was acting up but maybe I wasn't watching it close enough... ... .

Again thanks a bunch...

bob r...

 

[GerryDrake]

Oops

Sounds like me a couple of weeks ago. Trying and trying to log into 3 different Credit Union accounts online. Couldn't do it-wrong password. Called them on the phone and the gentleman very politely asked me to check to see if I had the caps-lock key on..... ... ... . duh... thank you sir, they all work fine now...

 

[Cattletrkr]

Danged 'puters. They'll getcha one way or another. :-laf :-laf :-laf :-laf

 

[DBond]

...

Still doesn't explain why the DTE was acting up but maybe I wasn't watching it close enough... ... .

Again thanks a bunch...

bob r...

Glad to hear that worked.



That DTE difference is close to the conversion between miles and km, maybe the US/M switch is flakey and is bouncing you between modes?