Our buses, like most modern vehicle have some form of computer chips in their engine management systems. Some of these work sensors that can get a little over sensitive and say some thing is wrong when there isn't. Usually a warning light goes on on the dash and the drivers gets on the radio and tells control. Their response is usually to switch every thing off, wait two minutes and try again. Some times controllers themselves can get a little over loaded as the following exchange heard on the radio illustrates:-
Driver. "Bus working 1234 to control."
Control. "Go ahead 1234."
Driver. "I have a problem, I am at the terminus and I have a puncture."
Control. "Switch everything off, wait two minutes and try again. Let me know if the problem persists."
Two minutes go by.
Driver. "Bus working 1234. I switched everything off and tried again like you said. I still have a puncture."