Idle Mode

IDLE MODE
Then the engine is at operating temperature, this is a Closed Loop mode. At idle speed, the Jeep/Truck Engine Controller (JTEC) receives inputs from:
- Air conditioning select signal (if equipped)
- Air conditioning request signal (if equipped)
- Battery voltage
- Crankshaft position sensor
- Engine coolant temperature sensor
- Intake manifold air temperature sensor
- Manifold absolute pressure (MAP) sensor
- Throttle position sensor (TPS)
- Camshaft position sensor signal (in the distributor)
- Battery voltage
- Park/neutral switch (gear indicator signal-auto. trans. only)
- Oxygen sensor

Based on these inputs, the following occurs:
- Voltage is applied to the fuel injectors through the Auto Shutdown (ASD) relay by the Jeep/Truck Engine Controller (JTEC). The JTEC will then control injection sequence and injector pulse width by turning the ground circuit to each individual injector on and off.
- The JTEC monitors the 02S sensor input and adjusts air-fuel ratio by varying injector pulse width. It also adjusts engine idle speed through the idle air control (IAC) motor.
- The JTEC adjusts ignition timing by increasing and decreasing spark advance.
- The JTEC operates the A/C compressor clutch through the clutch relay. This happens if A/C has been selected by the vehicle operator and requested by the A/C thermostat.

NOTE: The optional Extended Idle Switch is used to raise the engine idle speed to approximately 1000 rpm. This is when the shifter is in either the Park or Neutral position. A rocker-type 2-wire switch (extended idle switch) is mounted to the instrument panel. This switch will supply a ground circuit to the Jeep/Truck Engine Controller (JTEC). The switch is available only with the optional police package.