EGR Valve

Tiny
NYGFAN
  • MEMBER
  • 2004 CHEVROLET TAHOE
  • V8
  • 4WD
  • AUTOMATIC
  • 109,000 MILES
Where is the egr valve located on a 2004 Chevy Tahoe 5.3L Z71 flex fuel
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Tuesday, January 11th, 2011 AT 4:36 PM

14 Replies

Tiny
JACOBANDNICKOLAS
  • EXPERT
Hello,

The EGR valve is located at the front of the engine on the right side. Here is a video to show you how to test it. You should know that some do not have an EGR valve.

https://youtu.be/DqUCbbKdWf4

Check out the diagrams (Below)

Please let us know if you need anything else to get the problem fixed.

Cheers
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Thursday, March 3rd, 2011 AT 5:11 PM
Tiny
MARKVDB
  • MEMBER
  • 2002 CHEVROLET TAHOE
  • V8
  • 4WD
  • AUTOMATIC
  • 77,000 MILES
Engine Performance problem
2002 Chevy Tahoe V8 Four Wheel Drive Automatic 77000 miles

My tahoe was doing the rough idle/ nearly stall problem and threw a p0170/p0174 code, so I replaced the MAF sensor. After installing the sensor it also threw a p0300 code. I cleared all codes and disconnected the battery for a couple of minutes. Since then I haven't noticed a rough idle except when below freezing outside untill the engine warms up. There have been no new codes. No vacuum leaks that I can find. The current problem is horrible gas mileage. Like 8 to 10 highway. Fuel pressure is good, new plugs and wires so I am suspecting egr valve (I have seen that on 2 previous GMs Ive owned) I removed the intake cover but can't find the egr valve anywhere. Where the heck is it? 5.3L VIN code T
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Friday, March 30th, 2018 AT 1:13 PM (Merged)
Tiny
MATHIASO
  • MEMBER
Hello markvdb
hope this can help,

Pin Wire Color Circuit No. Function
A WHT 257 Exhaust Gas Recirculation (EGR)
B PPL 719 Sensor Return
C BRN 1456 Exhaust Gas Recirculation Solenoid Position Signal
D GRY 596 Reference Voltage Feed (5 Volt)
E RED 1676 Exhaust Gas Recirculation Solenoid Feed


http://www.2carpros.com/forum/automotive_pictures/46384_0996b43f8020287f_1.jpg



location:


http://www.2carpros.com/forum/automotive_pictures/46384_0996b43f8020287e_1.jpg

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Friday, March 30th, 2018 AT 1:13 PM (Merged)
Tiny
MARKVDB
  • MEMBER
I was wrong, it is an engine code Z. Evidently it doesn't even have an egr valve. Back to the drawing board.
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Friday, March 30th, 2018 AT 1:13 PM (Merged)
Tiny
MATHIASO
  • MEMBER
Hello,

P0170
P0174
The 2 codes point at the oxygen sensors,
What you should look again is for vacuum leaks - check for failed or loose vacuum lines, leaking intake gaskets, intake air tubes loose or any other source of un-metered air leaks (leaks after the Mass Air Flow Sensor)
2. Restricted fuel filter or bent/pinched fuel system lines (the last one could happens when jacking the car up on fuel line)
3. Incorrect input from other sensors, such as the Mass Air Flow Sensor wiring, which may not always drop a separate code
4. Engine misfire -. You might think that if there is a misfire then you will have all that unburned fuel and it should read rich; right? Well the O2 sensors read only oxygen content in the exhaust, so if you have all that unburned fuel from incomplete combustion then, you guessed it, you also have all that unburned oxygen. High O2 content in exhaust equals a lean reading!
EGR system will typically set a separate code. A leak in the exhaust system before the O2 sensor will also cause incorrect readings. And always check for after- market modifications. These can throw a wrench into the works! The only other possibilities (however unlikely), are wiring issues, computer concerns or a bad O2 sensor.
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Friday, March 30th, 2018 AT 1:13 PM (Merged)
Tiny
MARKVDB
  • MEMBER
I guess the next step is O2 sensors, although it hasnt thrown any codes for nearly 3 months. Runs ok except a little on the weak side power wise on acceleration and the bad gas mileage. Question is, which O2 sensor to start with? I've cleaned the throttle body plate, there was a layer of tar-like garbage behind the plate.
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Friday, March 30th, 2018 AT 1:13 PM (Merged)
Tiny
MATHIASO
  • MEMBER
Hello

P0171 is on bank 1
Bank1 is the side with the cylinder #1
P0174 is on bank 2 on the other side.
Here is the diagram,


http://www.2carpros.com/forum/automotive_pictures/46384_0996b43f8022f596_1.jpg



I have a marker on the side where the bank 1 is, oxygen sensors on that side.
Code does not say" sensor 1 before the catalytic converter and sensor 2 after the catalytic converter
So is the code p0174 on the other side.
Not all the oxygen sensors fail same time.
Have the injectors cleaned (walmart is cheap)
check for vacuum leak around the intake.
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Friday, March 30th, 2018 AT 1:13 PM (Merged)
Tiny
MARKVDB
  • MEMBER
Which sensors generally go bad giving the P0171 or P0174 code, before or after the converters?
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Friday, March 30th, 2018 AT 1:13 PM (Merged)
Tiny
MATHIASO
  • MEMBER
If Short Term + Long Term Fueling > 25% FOR TIME > 100 SEC.
P 0171 is set.
Your sensors are good, check for vacuum leak around the intake
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Friday, March 30th, 2018 AT 1:13 PM (Merged)
Tiny
KNOLLAD
  • MEMBER
Markvdb,

Did you solve your issue? My Tahoe has recently started to exhibit the exact same problems you have. I am about to replace the intake manifold gasket.

Thanks
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Friday, March 30th, 2018 AT 1:13 PM (Merged)
Tiny
MARKVDB
  • MEMBER
  • 2002 CHEVROLET TAHOE
  • V8
  • 4WD
  • AUTOMATIC
  • 77,880 MILES
Engine Performance problem
2002 Chevy Tahoe V8 Four Wheel Drive Automatic 77880 miles

Every diagram I've seen on my 02 Hoe (VIN Z) 5.3L shows an egr valve attached to a tube coming off of the passenger side exhaust manifold. The exhaust manifold on mine has a solid end. No tube, and I can't find an egr valve anywhere. What's up. Did it not have one, or had the manifold been replaced in the 20k miles before I bought it?
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Friday, March 30th, 2018 AT 1:13 PM (Merged)
Tiny
BLUELIGHTNIN6
  • EXPERT
Hello and thanks for donating

yes the 5.3L should have an EGR valve at the top right front of engine, if it's gone then previous repairs must have been made, although I don't believe the vehicle would run very well without the EGR valve if it was originally equipped with it.
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Friday, March 30th, 2018 AT 1:13 PM (Merged)
Tiny
LANDSCAPE1969
  • MEMBER
  • 2002 CHEVROLET TAHOE
  • V8
  • 4WD
  • AUTOMATIC
  • 180,000 MILES
Engine Mechanical problem
2002 Chevy Tahoe V8 Four Wheel Drive Automatic 180000 miles

went to get a smog check it did not pass because the mechanic could not find the egr valve. So on this model tahoe z71 w/5.3 motor where is it?
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Friday, March 30th, 2018 AT 1:14 PM (Merged)
Tiny
RASMATAZ
  • MEMBER
EGR Valve is located on top right of engine-see diagram below:


http://www.2carpros.com/forum/automotive_pictures/12900_egr_17.jpg

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Friday, March 30th, 2018 AT 1:14 PM (Merged)

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