Here is some info on it that might help you...Jim............DTC P0496
This DTC tests for undesired intake manifold vacuum flow to the evaporative emission (EVAP) system. The control module seals the EVAP system by commanding the EVAP canister purge solenoid valve OFF and the EVAP canister vent solenoid valve ON. The control module monitors the fuel tank pressure (FTP) sensor to determine if a vacuum is being drawn on the EVAP system. If vacuum in the EVAP system is more than a predetermined value within a predetermined time, this DTC sets.
The table illustrates the relationship between the ON and OFF states, and the Open or Closed states of the EVAP canister purge and vent solenoid valves.
CONDITIONS FOR RUNNING THE DTC
DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0125, P0128, P0442, P0443, P0446, P0449, P0452, P0453, P0455, P1106, P1107, P1111, P1112, P1114, P1115, P1125, P1516, P1518, P2101, P2107, P2108, P2119, P2120, P2125, P2135, P2138 are not set.
The ignition voltage is between 10-18 volts .
The barometric pressure (BARO) is more than 74 kPa .
The fuel level is between 15-85 percent .
The engine coolant temperature (ECT) is between 4-30C (39-86F) .
The intake air temperature (IAT) is between 4-30C (39-86F) .
The start up ECT and IAT are within 9C (16F) of each other.
CONDITIONS FOR SETTING THE DTC
The control module detects vacuum during a non-purge condition.
ACTION TAKEN WHEN THE DTC SETS
The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
CONDITIONS FOR CLEARING THE MIL/DTC
The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Clear the MIL and the DTC with a scan tool.
The problem was that evap selenoid valve was stuck open located in the intake manifold....had to order one from the dealership and was out of stock. Salesperson at dealership told me that they are going like hotcakes :ROFL