Is there any chance that anyone can post the EGR R&R instructions and any other related information? My SI2000 doesn't go new enough.


Some are claiming EGR codes when removing cats. I assume the same results would occur when removing or blocking the egr? Where is the sensor that determines sufficient egr flow?



ThanksEdited by: Max Power

<H1>Exhaust Gas Recirculation (EGR) System Description</H1>


The Exhaust Gas Recirculation (EGR) System is used to reduce the amount of nitrogen oxide (NOx) emission levels caused by high combustion temperatures. At temperatures above 1 371°C (2,500°F), oxygen and nitrogen combine to form oxides of nitrogen (NOx). Introducing small amounts of exhaust gas back into the combustion chamber displaces the amount of oxygen entering the engine. With less oxygen in the air/fuel mixture, the combustion pressures are reduced, and as a result, combustion temperatures are decreased, restricting the formation of NOx.


The EGR valve motor is a direct current (DC) stepper motor utilizing a worm gear that extends from the motor to push on the EGR valve stem. The worm gear is not attached to the valve stem, and can only force the valve open. A return spring is used to force the valve closed.


The mass air flow (MAF) sensor signal is used by the engine control module (ECM) to detect the proper amount of EGR flow. One EGR flow test is performed per ignition cycle. The ECM will close the EGR valve for 5 seconds, then open the EGR valve to 100 percent for 5 seconds. The ECM will then calculate the MAF difference and determine if the proper EGR flow has been detected.<A name=ss1-1369855><A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1369855&amp;psdid=437&amp;evc=sm#ss1-1369855" target="_blank">
<H5>Exhaust Gas Recirculation (EGR) System Operation</A></H5>
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<MAP name=1382620.map>
<TABLE>
<T>
<TR>
<TH align=left></TH></TR>
<TR>
<TD align=middle>(1)</TD>
<TD align=left>EGR Valve Position Sensor</TD></TR>
<TR>
<TD align=middle>(2)</TD>
<TD align=left>EGR Valve Worm Gear</TD></TR>
<TR>
<TD align=middle>(3)</TD>
<TD align=left>EGR Valve Return Spring</TD></TR>
<TR>
<TD align=middle>(4)</TD>
<TD align=left>EGR Valve Head</TD></TR>
<TR>
<TD align=middle>(5)</TD>
<TD align=left>EGR Valve Stem</TD></TR>
<TR>
<TD align=middle>(6)</TD>
<TD align=left>EGR Valve Motor</TD></TR></T></TABLE>


The exhaust gas recirculation (EGR) valve is controlled by the engine control module (ECM) through the EGR motor high control and EGR motor low control circuits. The ECM supplies voltage that is near ignition voltage to the high and low control circuits at all times. This voltage is used by the ECM as a reference voltage during non EGR operation in order to detect circuit failures. The ECM will pulse width modulate (PWM) the low control circuit to ground and an increase in amperage on the high control circuit can be observed with a DMM when the EGR valve is commanded open. A lower pulse width will increase the open position of the valve. In order to close the EGR valve, the ECM will PWM the high control circuit to ground.


When the ignition is turned ON, the ECM will drive the EGR motor worm gear out with just enough force to touch the EGR valve stem. The ECM will do this 3 times in quick succession. This action determines the minimum closed position of the valve and only happens once per ignition cycle. If the valve is prevented from closing all of the way after the minimum closed position is learned, the scan tool EGR Position parameter will not reflect this position until the next ignition cycle. The EGR motor worm gear is not connected to the EGR valve stem and can only push the valve open. The valve is returned to the closed position by a return spring.


The ECM uses the EGR position sensor to determine the position of the EGR valve. The ECM sends a reference voltage through the 5-volt reference circuit to the EGR position sensor. The ECM provides a vol

<H1>Inspection/Maintenance (I/M) Exhaust Gas Recirculation (EGR) System Set Procedure</H1><A name=ss1-1361262><A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1361262&amp;psdid=437&amp;evc=sm#ss1-1361262" target="_blank">
<H5>Description</A></H5>


The purpose of this test is to satisfy the enable criteria necessary to execute an Inspection/Maintenance (I/M) system monitor for the Exhaust Gas Recirculation (EGR) system. The system monitor is comprised of the test results from one or more DTCs. This procedure may be used to set the EGR I/M System Status display on the scan tool to YES. The EGR I/M System Status display indicated whether or not the control module has completed the system monitor. The system monitor completes when either all DTCs comprising the monitor run and pass, or any DTC comprising the monitor illuminates the malfunction indicator lamp (MIL). If one of the DTCs comprising the monitor is set and the MIL is not illuminated, the necessary trips are required to illuminate the MIL before the monitor will complete. Once the monitor completes, the EGR I/M System Status display will be updated to YES.<A name=ss2-1361262><A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1361262&amp;psdid=437&amp;evc=sm#ss2-1361262" target="_blank">
<H5>Conditions for Running</A></H5>
<UL =BULLET>
<LI>The barometric pressure (BARO) is more than 74 kPa.
<LI>The engine coolant temperature (ECT) is between 60-96.75°C (140-206.2°F).
<LI>The intake air temperature (IAT) is more than 5.25°C (41.5°F).
<LI>The battery voltage is between 11-18 volts. </LI>[/list]<A name=ss3-1361262><A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1361262&amp;psdid=437&amp;evc=sm#ss3-1361262" target="_blank">
<H5>Diagnostic Aids</A></H5>


If there is an impending failure, the system may require more time to run the diagnostic than was allotted in the system set procedure. If any DTCs do not run and no DTC is set, review the appropriate scan tool data list and service information. This will give an indication of why the DTCs do not run. Some may abort due to changes in the conditions while running. For example, changes in engine load such as a cooling fan or A/C compressor clutch turning ON, may cause a DTC to abort. If the EGR I/M System Status does not update to YES, the procedure can be repeated until a YES status is achieved.
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<T>
<TR>
<TH vAlign=bottom align=middle>


Step</TH>
<TH vAlign=bottom align=middle>


Action</TH>
<TH vAlign=bottom align=middle>


Yes</TH>
<TH vAlign=bottom align=middle>


No</TH></TR>
<TR>
<TD vAlign=center align=middle><A name=S01>


1 </A></TD>
<TD vAlign=top align=left>


Did you perform the Inspection/Maintenance (I/M) System Check?</TD>
<TD vAlign=bottom align=middle>


Go to Step 2 (http://service.gm.com/servlets/BlobShtml?ShtmlFile=1361262&amp;psdid=437&amp;evc=sm#S02) </TD>
<TD vAlign=bottom align=middle>


Go to Inspection/Maintenance (I/M) System Check (http://service.gm.com/servlets/CellHandler?CellId=84096&amp;RefDoc=1361262&amp;evc=sm) </TD></TR>
<TR>
<TD vAlign=center align=middle><A name=S02>


2 </A></TD>
<TD vAlign=top align=left>

<LI =1>Ensure that the vehicle is within the Conditions for Running specified in the supporting text.
<LI =1>Turn OFF all of the accessories, e.g., A/C, blower fan, etc.
<LI =1>Start and allow the engine to idle for 2 minutes.
<LI =1>Observe the I/M System Status display with a scan tool. </LI>


Did the Exhaust Gas Recirculation (EGR) System Status update to YES?</TD>
<TD vAlign=bottom align=middle>


Go to Step 5 (http://service.gm.com/servlets/BlobShtml?ShtmlFile=1361262&amp;psdid=437&amp;evc=sm#S05) </TD>
<TD vAlign=bottom align=middle>


Go to <A href="http://service.gm.com/servlets/BlobShtml?ShtmlFi

<H1>Exhaust Gas Recirculation (EGR) System Cleaning</H1>



<H4>Caution</H4>


Avoid breathing fumes and swallowing EGR exhaust deposits when removing components for cleaning as bodily injury may result.




<LI =1>Remove the exhaust gas recirculation (EGR) cooler tube. Refer to Exhaust Gas Recirculation (EGR) Valve Cooler Tube Replacement (http://service.gm.com/servlets/CellHandler?CellId=84184&amp;RefDoc=1381391&amp;evc=sm) .
<LI =1>Depress the pintle several times using a pencil eraser or other suitable soft instrument. The pintle should move in and out smoothly. Replace the valve if the valve exhibits tendencies to stick.
<LI =1>Try to rotate the EGR valve electrical connector housing. Repeat for the coil housing. Replace the valve if the valve exhibits any looseness. Inspect the EGR valve pintle and seat for deposits. Use a cloth or other suitable soft device to remove the deposits. Remove all loose particles. Replace the valve if the deposits are such that the pintle to base interface cannot be cleaned adequately to allow the pintle to seal against the seat. Damage to the powdered metal EGR valve base occurs if cleaned with solvents, sharp tools, wire brush or wheel, or sand blasting. Cleaning by these methods is not recommended.
<LI =1>Clean the passages with a wire brush. Remove all loose particles.
<LI =1>Install the EGR cooler tube. Refer to Exhaust Gas Recirculation (EGR) Valve Cooler Tube Replacement (http://service.gm.com/servlets/CellHandler?CellId=84184&amp;RefDoc=1381391&amp;evc=sm) . </LI>

<H1>Exhaust Gas Recirculation (EGR) Valve Replacement</H1><A name=ss1-1381388><A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1381388&amp;psdid=437&amp;evc=sm#ss1-1381388" target="_blank">
<H5>Removal Procedure</A></H5>

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<LI =1>Remove the exhaust gas recirculation (EGR) cooler tube. Refer to Exhaust Gas Recirculation (EGR) Valve Cooler Tube Replacement (http://service.gm.com/servlets/CellHandler?CellId=84184&amp;RefDoc=1381388&amp;evc=sm) .
<LI =1>Remove the EGR valve bolts (3).
<LI =1>Remove the EGR valve/solenoid assembly (1).
<LI =1>Remove and discard the EGR valve/solenoid assembly gasket (2). </LI><A name=ss2-1381388><A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1381388&amp;psdid=437&amp;evc=sm#ss2-1381388" target="_blank">
<H5>Installation Procedure</A></H5>

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<LI =1>Install a NEW EGR valve/solenoid assembly gasket (2).
<H4>Notice</H4>


Refer to Fastener Notice (http://service.gm.com/servlets/CellHandler?CellId=10105&amp;RefDoc=1381388&amp;evc=sm) in Cautions and Notices.
<LI =1>Install the EGR valve/solenoid assembly (1).
<LI =1>Install the EGR valve bolts. Tighten


Tighten the bolts to 20 N·m (15 lb ft).
<LI =1>Install the EGR cooler tube. Refer to Exhaust Gas Recirculation (EGR) Valve Cooler Tube Replacement (http://service.gm.com/servlets/CellHandler?CellId=84184&amp;RefDoc=1381388&amp;evc=sm) </LI>

Since the return spring is used to close the EGR is it safe to assume that when the truck is off, the EGR will be closed and not allow any exhaust gas to recirculate?