K 1500 Suburban 4WD V8-5.7L VIN R (1997)
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The Engine Coolant Temperature (ECT) sensor.
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The EGR Pintle position sensor.
Output messages are then sent to the EGR system indicating the proper amount of exhaust gas recirculation with intake air necessary in order to lower
the combustion temperatures. This electronic metering of exhaust gas is ten times faster than the vacuum-operated models as well as an improved
diagnostic capabilities.
CONNECTOR
Positioned at the top of the linear EGR assembly are 5 terminals.
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A is the pulse width modulated negative signal from the control module.
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B is the sensor ground.
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C is the sensor output.
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D is the +5 volts supply.
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E is the positive from ignition.
OPERATION
A 12 volt current which enters the valve through an electrical connector (terminal E) energizes the solenoid (bobbin and coil) assembly. The 12 volt
current then flows through the solenoid assembly to the control module and creates an electromagnetic field. This field causes the armature assembly to
be pulled upward, lifting the pintle a variable amount off the base.
The exhaust gas then flows from the exhaust manifold through the orifice into the intake manifold.
The pintle position sensor (sensor cap) reads the height of the pintle, and the control module closes the loop on a desired position versus the actual
position read. This changes the pulse width modulated command to the solenoid accordingly, until the actual pintle position equals the desired pintle
position.
The linear EGR valve is unique in that the control module continuously monitors the pintle height and continuously corrects it in order to obtain accurate
flow, making linear EGR a Closed Loop system. When the solenoid is de-energized (the control module breaks the circuit), the pintle seals against the
orifice, blocking the exhaust flow to the intake manifold.
