Can not get EGR and EVAP monitors to set

Tiny
LISA GUTIERREZ
  • MEMBER
  • 2008 CHEVROLET EQUINOX
  • 3.4L
  • 6 CYL
  • AWD
  • AUTOMATIC
  • 160,000 MILES
Drove many drive cycles and the EGR and evaporator monitors will not set! Drove at least five hundred miles, had put new fuel pump, purge valve, EGR valve, new gas cap, plug, wires. We have had three ten day moving permits and now we are going have to start paying for the ten day moving permits daily. This truck is driving me crazy just do not understand why it will not set.I thank you for hearing my troubles and appreciate any information on this matter. Yours truly, so frustrated!
Friday, January 27th, 2017 AT 6:15 PM

5 Replies

Tiny
STEVE W.
  • MECHANIC
  • 13,974 POSTS
EGR Monitor:
Prerequisites: no codes present (even a pending code), engine coolant temperature is above 75 degrees f; barometric pressure above 72kPa.

1. Idle vehicle five minutes or until it is in closed loop.
2. Accelerate and drive for one minute at steady speed above fifty mph.
3. Coast vehicle down to twenty mph (vehicle in drive, do not use the brakes).
4. Repeat steps two and three four times.

The EVAP can be a real bear to set because it takes a very narrow set of conditions to make it set.
For instance if the fuel tank is under 1/4 or over 3/4 of a tank it won't run the test.
If the engine and air temperatures do not match it won't run the test.
I have seen the EVAP take a month to set.

You also may want to visit a dealer and have them scan it with a dealer level tool. There are a couple items that set codes that do not turn on the CEL but will block the monitor tests from running.
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Friday, January 27th, 2017 AT 7:14 PM
Tiny
LISA GUTIERREZ
  • MEMBER
  • 3 POSTS
Okay, I understand but I live in residential area cant get to fifty mph for at least five miles down the road. So do I let it idle then go the residential speed limit twenty five to thirty five until I am able to get up to fifty mph? This is the part that I do not quite understand. I thank you for taking out your time to respond to me. This is just plain ridiculous a good running vehicle and cannot get it smogged. OMG!
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Friday, January 27th, 2017 AT 9:47 PM
Tiny
STEVE W.
  • MECHANIC
  • 13,974 POSTS
You can drive it out to an area that you can go fifty mph at. Then shut it off. Start it and follow the guide. It should set at least the EGR. As I said, some of these monitors are a real PIA.
If it does not set, take it to a dealer/shop and have them make sure you do not have some odd code set or pending. There are codes that do the same kind of crud that the monitors do. They may trigger and then get held in memory for a week until the trigger happens again and the light finally goes on.
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Saturday, January 28th, 2017 AT 1:06 AM
Tiny
LISA GUTIERREZ
  • MEMBER
  • 3 POSTS
Thank you Steve. I am going to try this and I swear if it does not set I am driving it off a cliff. Haha, lol!
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Saturday, January 28th, 2017 AT 3:59 AM
Tiny
STEVE W.
  • MECHANIC
  • 13,974 POSTS
I actually had a friend who got so fed up trying to repair a car that he decided to part it out. He sold most of the parts on eBay and actually ended up making more than he had paid for the car!
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Saturday, January 28th, 2017 AT 7:52 AM

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