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HOMESERVICE MANUALSFORD2004FREESTAR V6-4.2L VIN 2REPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTCOMPUTERS AND CONTROL SYSTEMSDESCRIPTION AND OPERATIONELECTRONIC ENGINE CONTROLS COMPONENTS
2004 Ford Freestar V6-4.2L VIN 2
Electronic Engine Controls Components
2004 Ford Freestar V6-4.2L VIN 2SECTION Electronic Engine Controls Components
ELECTRONIC ENGINE CONTROLS
The electronic engine controls consist of the following:
- powertrain control module (PCM)
- throttle position (TP) sensor
- idle air control (IAC) valve
- cylinder head temperature (CHT) sensor
- camshaft position (CMP) sensor
- crankshaft position (CKP) sensor
- mass air flow (MAF) sensor
- heated oxygen sensor (HO2S)
- catalyst monitor sensor
- vehicle speed sensor (VSS)
- intake manifold runner control (IMRC)
The PCM needs the following inputs to calibrate the engine correctly:
- crankshaft position
- intake air temperature
- engine load (manifold pressure)
- engine rpm
- engine coolant temperature
- camshaft position
The TP sensor:
- sends the PCM a signal indicating the throttle plate angle.
- is the main input to the PCM from the driver.
The IAC valve:
- controls bypass air around the throttle plate.
- is controlled by the PCM.
The CHT sensor:
- sends the PCM a signal indicating cylinder head temperature.
- resistance decreases as coolant temperature increases.
The CMP sensor:
- sends the PCM a signal indicating camshaft position used for fuel synchronization.
The CKP sensor:
- sends the PCM a signal indicating crankshaft position.
- is essential for calculating spark timing.
The MAF sensor:
- sends the PCM a signal indicating mass air flow rate of air entering the engine.
The IAT sensor:
- sends the PCM a signal indicating the temperature of the air entering the engine.
- resistance decreases as temperature increases.
The HO2S:
- has the ability to create a voltage signal dependent on exhaust oxygen content.
- provides feedback information to the PCM used to calculate fuel delivery.
The Catalyst Monitor Sensors:
- monitor oxygen content after it flows through the catalytic converter.
- provides a voltage to the PCM used to calculate catalytic converter integrity.
The (VSS):
- sends a signal to the PCM indicating wheel speed.
The air induction system improves engine performance by using the intake manifold runner control (IMRC) assemblies as follows:
- The lower intake manifold has two runners per cylinder, feeding each of the intake ports in the cylinder heads.
- The IMRC assemblies are located between the upper intake manifold and cylinder heads, providing two air passages for each cylinder.
- One air passage is always open and the other passage switches from closed to open by means of a valve plate.
- Below 1,500 rpm, this valve plate is closed to improve fuel economy and emissions.
- Above 1,500 rpm, this valve plate opens to improve high speed engine performance.
The valve plates are opened and closed by the IMRC electric actuator, which is controlled by the PCM.
The electronic engine controls consist of the following:
- powertrain control module (PCM)
- throttle position (TP) sensor
- idle air control (IAC) valve
- cylinder head temperature (CHT) sensor
- camshaft position (CMP) sensor
- crankshaft position (CKP) sensor
- mass air flow (MAF) sensor
- heated oxygen sensor (HO2S)
- catalyst monitor sensor
- vehicle speed sensor (VSS)
- intake manifold runner control (IMRC)
The PCM needs the following inputs to calibrate the engine correctly:
- crankshaft position
- intake air temperature
- engine load (manifold pressure)
- engine rpm
- engine coolant temperature
- camshaft position
The TP sensor:
- sends the PCM a signal indicating the throttle plate angle.
- is the main input to the PCM from the driver.
The IAC valve:
- controls bypass air around the throttle plate.
- is controlled by the PCM.
The CHT sensor:
- sends the PCM a signal indicating cylinder head temperature.
- resistance decreases as coolant temperature increases.
The CMP sensor:
- sends the PCM a signal indicating camshaft position used for fuel synchronization.
The CKP sensor:
- sends the PCM a signal indicating crankshaft position.
- is essential for calculating spark timing.
The MAF sensor:
- sends the PCM a signal indicating mass air flow rate of air entering the engine.
The IAT sensor:
- sends the PCM a signal indicating the temperature of the air entering the engine.
- resistance decreases as temperature increases.
The HO2S:
- has the ability to create a voltage signal dependent on exhaust oxygen content.
- provides feedback information to the PCM used to calculate fuel delivery.
The Catalyst Monitor Sensors:
- monitor oxygen content after it flows through the catalytic converter.
- provides a voltage to the PCM used to calculate catalytic converter integrity.
The (VSS):
- sends a signal to the PCM indicating wheel speed.
The air induction system improves engine performance by using the intake manifold runner control (IMRC) assemblies as follows:
- The lower intake manifold has two runners per cylinder, feeding each of the intake ports in the cylinder heads.
- The IMRC assemblies are located between the upper intake manifold and cylinder heads, providing two air passages for each cylinder.
- One air passage is always open and the other passage switches from closed to open by means of a valve plate.
- Below 1,500 rpm, this valve plate is closed to improve fuel economy and emissions.
- Above 1,500 rpm, this valve plate opens to improve high speed engine performance.
The valve plates are opened and closed by the IMRC electric actuator, which is controlled by the PCM.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.