General beat me to it. Tire imbalance will cause this. After it has been sitting, Walk around with a tire pressure gauge and check all the tires before a startup To figure out which wheel valve is leaking. Another giveaway for this is to shutdown the truck, get in under the truck and put a baloon or rubber glove over the exhaust horn on the dump valves. If it inflates, you have a wheel valve leaking and feeding air to the dump exhaust port.
CTIS controls these 4 air bombs we roll around on with a pea-brained processor using a lookup table, stop watch and a pressure sensor. It is expecting certain things to happen in a certain amount of time, and it is expecting pressure to be stable when it checks it. If you have a low tire, when CTIS seals the system, gives a shot of air to open the wheel valves and looks to measure pressure, the pressure is unstable as air flows to the low tire, and it faults…
The same thing happens if you change the load significantly. It will flunk the first pressure test as the weight on the rear axle has significantly changed the tire pressures on that axle.