Wrangler L6-4.0L VIN S (2000)
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Fuel level
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Generator (battery voltage) output
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Ignition circuit sense (ignition switch in run position)
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Intake manifold air temperature sensor
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Leak detection pump (if equipped)
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Manifold Absolute Pressure (MAP) sensor
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Oil pressure sensor
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Oxygen sensors
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Park/neutral switch (auto. trans. only)
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Power ground
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Power steering pressure switch (2.5L only)
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SCI receive (DRB scan tool 16-way connection)
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Sensor return
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Signal ground
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Speed control multiplexed single wire input
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Throttle position sensor
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Vehicle speed sensor
PCM Outputs
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A/C clutch relay
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Auto Shutdown (ASD) relay
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CCD bus (+/-) circuits for: speedometer, voltmeter, fuel gauge, oil pressure gauge/lamp, engine temp. gauge and speed control warn. lamp
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Duty cycle EVAP canister purge solenoid
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5 volt sensor supply (primary)
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5 volt sensor supply (secondary)
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Fuel injectors
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Fuel pump relay
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Generator field driver (-)
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Generator field source (+)
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Idle Air Control (IAC) motor
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Ignition coil
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Leak detection pump (if equipped)
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Malfunction indicator lamp (Check engine lamp). Driven through CCD circuits.
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SCI transmit (DRB scan tool 16-way connection)
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Speed control vacuum solenoid
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Speed control vent solenoid
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Tachometer (if equipped). Driven through CCD circuits.
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Transmission convertor clutch solenoid
PCM OPERATING MODES
As input signals to the powertrain control module (PCM) change, the PCM adjusts its response to output devices. For example, the PCM must
calculate a different injector pulse width and ignition timing for idle than it does for wide open throttle.
There are several different modes of operation that determine how the PCM responds to the various input signals.
There are two types of engine control operation: open loop and closed loop.
In open loop operation, the PCM receives input signals and responds according to preset programming. Inputs from the heated oxygen sensors are
not monitored.
In closed loop operation, the PCM monitors the inputs from the heated oxygen sensors. This input indicates to the PCM whether or not the
calculated injector pulse width results in the ideal air-fuel ratio of 14.7 parts air to 1 part fuel. By monitoring the exhaust- oxygen content through
the oxygen sensor, the PCM can fine tune injector pulse width. Fine tuning injector pulse width allows the PCM to achieve the lowest emission
levels while maintaining optimum fuel economy.
The engine start-up (crank), engine warm-up, and wide open throttle modes are open loop modes. Under most operating conditions, closed loop
modes occur with the engine at operating temperature.
Ignition Switch ON (Engine OFF) Mode
When the ignition switch activates the fuel injection system, the following actions occur:
1. The PCM determines atmospheric air pressure from the MAP sensor input to determine basic fuel strategy.
2. The PCM monitors the engine coolant temperature sensor and throttle position sensor input. The PCM modifies fuel strategy based on this
input.
When the key is in the "ON" position and the engine is not running (zero rpm), the auto shutdown relay and fuel pump relay are not energized.
Therefore, voltage is not supplied to the fuel pump, ignition coil, and fuel injectors.