Brake lights and engine brake

[T680]

Mine does too, it doesn't botter me though... With the very light weights I carry..don't need it much at all..

Last cab & engine update was on Ian '16 didn't notice it before that, can be seen at nite only,of course by one self

Although did asked dealer not touch the cab update, they had too, in order to be allowed to do engine one.????..so I was told

[Unilevers]

its in the cab controller. i 100% guarantee they sneak updated it, or flashed it in some way.

[schISM]

(12-21-2016 )Unilevers Wrote:  its in the cab controller. i 100% guarantee they sneak updated it, or flashed it in some way.

I'd be inclined to agree except I'm the only one who's plugged into the truck since last September when Peterbilt fixed an oil cooler leak. It didn't do it before I updated the cal. Now it does. I realize I'm working above my pay grade but "something" in the truck ecm has to trigger the cab ecm to let it know the jakes are active to trigger the brake lamps. I'd be hard pressed to tell any difference in the way it runs anyway, I might just go back to my old cal.

[Signature620]

Under engine brake control there is a parameter called "Engine Brake Lamp". Make sure it's disabled.

[Rawze]

(12-22-2016 )Signature620 Wrote:  Under engine brake control there is a parameter called "Engine Brake Lamp". Make sure it's disabled.

That setting is for a separate output pin on the ECM for the light in the dash to let the driver know if engine brakes are selected or not. It does NOT change state as the engine brakes are applied. Its function is to simply stay on the whole time you have engine braking enabled via the switch in the dash., and off if you have disabled engine brakes for trucks that do not use J1939 for the dash indicator lights.

Most trucks now have J1939 for reading the state of the engine brakes, etc., so that setting is not even used for most trucks any more.

I would seriously doubt that updating the software in only the ECM would cause a change in how the brake lights work,... but I will elaborate on it a bit if that is truly the case (doubtful though).

If updating only your ECM software truly did make the "brake light on" every time the engine brakes engage and dis-engage,.. then it was a SETTING IN THE CAB CONTROLLER THE WHOLE TIME!. -- What may have happened, is that the j1939 address may have changed in the calibration to the correct one for that brand/make of truck,.. AND NOW IT IS REPORTING THE ENGINE BRAKE STATE AS IT SHOULD!. WHAT THE CAB CONTROLLER CHOOSES TO DO WITH THAT IS NOT PART OF THE ENGINE!.


YOUR PROBLEM WITH BRAKE LIGHTS COMMING ON/OFF WITH THE ENGINE BRAKES IS IN THE CAB CONTROLLER -- NOT THE ENGINE!!!



Trying to edit the engine calibration to solve your problem IS NOT THE CORRECT SOLUTION AT ALL!!! -- DON'T MAKE A HALF-ASSED SOLUTION TO A PROBLEM YOU KNOW DAMN WELL WHAT THE CORRECT SOLUTION IS --- I.E. FIX IT IN THE CAB COINTROL SOFTWARE!!!>

[schISM]

Thanks Rawze, I don't have ESA so I'll have to see if Pete can do it for me. Thanks everybody for chiming in and Merry Christmas!!!