Ignition Switch (Key on) Mode

IGNITION SWITCH (KEY-ON) MODE
This is an Open Loop mode. When the fuel system is activated by the ignition switch, the following actions occur:
- The Jeep/Truck Engine Controller (JTEC) pre-positions the idle air control (IAC) motor.
- The JTEC determines atmospheric air pressure from the Manifold Absolute Pressure (MAP) sensor input to determine basic fuel strategy.
- The JTEC monitors the engine coolant temperature sensor input. The JTEC modifies fuel strategy based on this input.
- Intake manifold air temperature sensor input is monitored
- Throttle position sensor (TPS) is monitored
- The auto shutdown (ASD) relay is energized by the JTEC for approximately three seconds.
- The fuel pump is energized through the fuel pump relay by the JTEC. The fuel pump will operate for approximately three seconds unless the engine is operating or the starter motor is engaged
- The O2S sensor heater element is energized through the ASD relay. The O2S sensor input is not used by the JTEC to calibrate air-fuel ratio during this mode of operation.
- The up-shift indicator lamp is illuminated (manual transmission only).