RAM 2500 Truck 2WD V10-8.0L VIN W MDC (1999)
Fuel Filler Cap: Description and Operation
FUEL TANK FILLER TUBE CAP
The loss of any fuel or vapor out of filler neck is prevented by the use of a pressure-vacuum fuel tank filler tube cap. Relief valves inside the cap
will release fuel tank pressure at predetermined pressures. Fuel tank vacuum will also be released at predetermined values. This cap must be
replaced by a similar unit if replacement is necessary. This is in order for the system to remain effective.
CAUTION: Remove fuel tank filler tube cap before servicing any fuel system component. This is done to help relieve tank pressure. If equipped
with a California emissions package and a Leak Detection Pump (LDP), the secondary seal below the fill cap must be pressed (opened) to relieve
fuel tank pressure.
