Ignition Switch-ST and Park/Neutral (Inhibitor) Switch (A/T)

Operation

The ignition switch-ST inputs HIGH-level signais to the engine control module during engine cranking. The engine control module, based on those signals, regulates fuel injection during starting, etc.

When the ignition switch is set to START, the battery voltage during engine cranking is, by way of the ignition switch and the park/neutral position switch, applied to the engine control module, and the engine control module thus detects the fact that the engine is cranking.

Note that battery voltage is not applied to the engine control module if the position of the selector lever is other than the "P" or "N" range.

The park/neutral position switch functions to convert the voltage to HIGH level or LOW level depending upon whether the selector lever is at the "P" or "N" range or is at some position other than the "P" or "N" range, and inputs the result to the engine control module. The engine control module, based upon those signals, then regulates the operation of the idle speed control motor.

Battery voltage within the engine control module is applied, by way of the resistance, to the park/neutral position switch. When the selector lever is set to the "P" or "N" range, continuity is created, via the starter motor, between the engine control module's park/neutral position switch terminal and ground, and the terminal voltage becomes LOW level.

Troubleshooting Hints

If the output of the park/neutral position switch is abnormal even though the results of the checking of the park/neutral position switch harness and of the component itself are normal, it is probable that the cause is improper adjustment of the control cable.




Inspection




Harness Inspection