125 ± 5 psi (862 ± 34 kPa) must be
supplied to trailer air system before
troubleshooting can begin.
Air lines and valves listed in this
troubleshooting procedure are illustrated
and located in FO-2.
(1) Push in trailer charge valve in truck
(2) Listen for leaks from the following
components air lines 2254, 2223,
2620, 2605, 2424, 2228, 2548, 2019,
2606, 2014, fittings, parking brake
control valve, inversion valve, air bag
control valve, air reservoirs, brake
relay valves, and multifunction valve.
(a) If fittings leak and are loose,
(b) If air hose(s) leak, perform Steps
(3) and (4) below and repair or
replace air hose(s) (see schematic
(c) If any of the components listed
above leak, perform Steps (3)
and (4) below and replace them
according to maintenance
procedures (Chapter 4).
(d) If all of Items above are OK,
perform Steps (3) and (4) below
and go to Step (2) of this Fault.
(3) Pull out trailer charge valve in truck.
(4) Turn OFF ENGINE switch.