Supersedes Technical Service Bulletin Group 01 number 13-38 dated October 23, 2013. MIL on. DTCs are stored in the engine control module (ECM). Drivability is not affected. The leak detection pump (LDP) is a vacuum-driven, ECM-controlled, diaphragm pump. In order for the LDP to operate, the engine must be running and vacuum must be applied to the vacuum switch on the LDP. The LDP pressurizes the EVAP system and monitors any pressure drop within a specified amount of time in order to detect a leak. DTC P0456 or DTC P0442 can be stored due to static or sporadic air leaks in the EVAP system or static or sporadic air leaks in the LDP.
