"Read On/Off" Command Menu
"READ ON/OFF" COMMAND MENUValues relating to the different commands are stored in the electronic control module's internal memory. These values are updated continuously, some of them as soon as the ignition switch is turned to the ON position although most of them require the engine to be started.
When the engine is switched OFF the control module stores the most recent value recorded. This value is displayed next time the ignition switch is turned to the ON position but it is not relevant for commands requiring the engine to be started. The Scan Tool will then display an incorrect value.
Some readings will swing between two limits when the command function is correct. To enable a correct function to be determined, the Scan Tool incorporates a filter circuit with a long time constant.
If a command of this kind is entered, the Scan Tool may display "NOT ACTIVE' 0-5 seconds before "ACTIVE" is displayed. Relevant commands: "CRANKSHAFT POSITION", "CAMSHAFT POSITION", "IGNITION COIL 1+4", "IGNITION COIL 2+5" and "IGNITION COIL 3+6".
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