Service Brake System ... (tuning help)

[Flyer]

I posted this on Tech, but figured I'd try here as well.


I'm tuning on an 04 4x4 with 315/75/16's and a 3.73 rear. The stock setting on the tire was 29.something, I changed it to 35 to correct the speedo, but now it's throwing the Service Brake System message. I checked Nitto's site and they said the tire's actually 34.5, so I changed it to that hoping that's what it was, no luck.

Anyone else had this problem? What was it and what fixed it?

It's kinda wierd cause it will do it when you turn the key on, you turn the ignition back off and back on and everything's OK. Run the truck a little more, kill it, next startup, the Service Brake message is back.

[4.8t]

mine does it any time i run up a tune but thats it then its gone i'm running procomp xterian 285/75r16
just a dumb question but did you check your brake fluid.

[bmfcamaro]

there is nothing wrong with your truck i had the same problem. what it is is the bcm( brake control module). you programed the vcm, but with our software we can not program the bcm. so you vcm says 35 and you bcm says 29. it thinks big problem throw codes. get someone with a tech 2 and put the biggest tire settings they can i think mine ended up being a 19 inch something or other. basically as close as you can. hope that helped.

[NSTLLMNGR]

SAME PROBLEM HERE!!!!

[bmfcamaro]

get someone with a tech II to modify your bcm. i had the same problem fixed in no time