Grand Cherokee 2WD L6-4.0L VIN S (1997)
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Crankshaft Position (CKP) Sensor
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Intake Manifold Air Temperature (IAT) Sensor
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Manifold Absolute Pressure (MAP) Sensor
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Throttle Position Sensor (TPS)
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Camshaft Position Sensor (CPS) signal (in the distributor)
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Park/neutral switch (gear indicator signal-auto. trans. only)
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Oxygen (O2S) sensors
Based on these inputs, the following occurs:
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Voltage is applied to the fuel injectors with the Automatic Shutdown (ASD) relay via the PCM. The PCM will then adjust the injector pulse width
by turning the ground circuit to each individual injector on and off.
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The PCM monitors the 02S sensor input and adjusts air-fuel ratio. It also adjusts engine idle speed through the Idle Air Control (IAC) motor.
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The PCM adjusts ignition timing by turning the ground path to the coil on and off.
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The PCM 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.
Deceleration Mode
DECELERATION MODE
When the engine is at operating temperature, this is an Open Loop mode. During hard deceleration, the Powertrain Control Module (PCM) receives
the following inputs.
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Air conditioning select signal (if equipped)
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Air conditioning request signal (if equipped)
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Battery voltage
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Engine coolant temperature sensor
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Crankshaft position sensor
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Intake manifold air temperature sensor
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Manifold Absolute Pressure (MAP) sensor
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Throttle Position Sensor (TPS)
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Camshaft position sensor signal (in the distributor)
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Park/neutral switch (gear indicator signal-auto. trans. only)
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Vehicle speed sensor
If the vehicle is under hard deceleration with the proper rpm and closed throttle conditions, the PCM will ignore the oxygen sensor input signal. The
PCM will enter a fuel cut-off strategy in which it will not supply a ground to the injectors. If a hard deceleration does not exist, the PCM will
determine the proper injector pulse width and continue injection.
Based on the above inputs, the PCM will adjust engine idle speed through the Idle Air Control (IAC) motor.
The PCM adjusts ignition timing by turning the ground path to the coil on and off.
Engine Start-Up Mode
ENGINE START-UP MODE
