Electrical Verification

With the ignition ON and the engine OFF, command each VLOM solenoid ON and OFF several times using the scan tool output control function. You should be able to hear the solenoid energize and de-energize with each scan tool output control command.

Mechanical Verification

1. Connect a vacuum gage to the EVAP vacuum tube fitting on the electronic throttle body. Do not use a compound pressure and vacuum gauge. The vacuum gage on a hand held vacuum pump, or Mityvac, will work fine for this test.
2. Allow the engine to reach normal operating temperature.
3. With a scan tool, command each Displacement on Demand (DoD) solenoid ON, one at a time. Each time a DoD solenoid is commanded ON, you should observe a fluctuating drop of 0.5-2 inches of Hg, or vacuum, on the gage. The drop in vacuum occurs because; both the intake and exhaust valves are de-activated for that cylinder. Also the engine will have a misfire when that cylinder is de-activated. For additional DoD mechanical testing, refer to Displacement on Demand (DoD) System Diagnosis .
   • If the vehicle passes the Circuit/System Verification Test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records Data List. The other option is to refer to Testing for Intermittent Conditions and Poor Connections .