Circuit Actuation Test Mode
When the Circuit Actuation Test Mode option is selected on the scan tool, you will have access to Actuator Test menus. The tests listed in the menu provide the capability to activate certain controlled output circuits to the PCM. The lists of tests available vary depending on engine and vehicle equipment. The tests may be used to find device faults that the PCM may not recognize.
During Actuator Tests, both electrical and mechanical activity can be checked and verified. Once a certain device is selected, the PCM activates the device that allows you to listen for an audible click or observe a visual indication of correct device operation.
The scan tool Actuator Test Mode can be used to diagnose many PCM controlled devices, and to help diagnose the cause of one or more trouble codes on these vehicles.
State Display Switch Test Mode
The PCM switch inputs have two recognized states: they are either in a HIGH or LOW state. Because these inputs are either high or low, the PCM may not be able to detect the difference between when a switch is in a high or low state from when a switch has a circuit problem (i.e., when a circuit is open, grounded or shorted or even if the switch is defective).
If the scan tool State Display (meaning the Switch State) shows a change from HIGH to LOW; or from LOW to HIGH when the selected switch is activated, it can be assumed that the entire switch circuit to the PCM is functioning properly. The scan tool State Display Mode can be used to diagnose these codes:
Testing Relays, Solenoids & Switches With Scan Tool
Refer to the specific instructions in the scan tool Operating Manual to test a particular device or its circuit.