Check engine - brake switch problem

[Paul Aronson]

I recently had the check engine light come on while driving on the Interstate. Light cleared after stopping the engine when refueling. Stopped at a repair shop and the engine had a "brake relay fault" code showing as nonactive.
Brake lights work fine, problem has not reappeared.
Can anybody tell me what causes this code to appear? I can find the stop light relay in the wiring diagram but cant follow it far enough to determine what causes the fault code.
Any help?

[Gerald Farris]

Paul,
A check engine light for a brake relay fault has nothing to do with your stop lights. It is related to your engine compression brake otherwise known as a Jake Brake.

Gerald

[Paul Aronson]

Thank you. I'll call Caterpillar onday and see if they can give me any specifics to look for.