RAM 2500 Truck 2WD L6-5.9L DSL Turbo VIN 7 (2001)
Vacuum Check Valve HVAC: Description and Operation
On models with this engine, a vacuum check valve is installed on the engine vacuum pump. The vacuum check valve is designed to allow vacuum to
flow in only one direction through the accessory vacuum supply circuits.
The use of a vacuum check valve helps to maintain the system vacuum needed to retain the selected HVAC mode and vehicle speed control settings. On
this engine models, it prevents oil from contaminating the vacuum supply system by maintaining vacuum in the pump after the engine is shut-off.
The vacuum check valve cannot be repaired and, if faulty or damaged, it must be replaced.
