CHECK ENGINE LIGHT CAME ON AFTER TURNING ON THE ...

  • Tiny
  • richardtaylor
  • 2002 Ford Expedition
  • 150,000 miles

Check engine light came on after turning on the heater codes says it is banks 1 an 2 running lean

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Sunday, December 9th, 2012 AT 11:00 PM

12 Replies

  • Tiny
  • saturntech9
  • Expert
  • 29,290 posts

I need the exact code numbers and engine size?

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Sunday, December 9th, 2012 AT 11:17 PM
  • Tiny
  • richardtaylor
  • Member

5.4L an the code were p0171 an p0174

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Sunday, December 9th, 2012 AT 11:41 PM
  • Tiny
  • saturntech9
  • Expert
  • 29,290 posts

Have you checked for a vacuum leak yet?Thats where I would start.

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Sunday, December 9th, 2012 AT 11:43 PM
  • Tiny
  • richardtaylor
  • Member

Yea we ran a smoke test did everything plugs fuel filter cuz it was doing it before with out the turning on the heater but last week it did it again hen we turned the heat on so I cleared the codes to make sure an right when we turned it on again it did it ive never heard of a heater makin it throw lean codes

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Sunday, December 9th, 2012 AT 11:48 PM
  • Tiny
  • saturntech9
  • Expert
  • 29,290 posts

Have you thought of maybe one of vacuum actuators are leaking vacuum causing the code when vacuum is applied or the hose to it?Thats all I can think of with the symptoms you are describing. So when you move the temp control all the way to max hot it triggers the code?

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Monday, December 10th, 2012 AT 12:23 AM
  • Tiny
  • richardtaylor
  • Member

No that I did think of ill try that thanks for ur help

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Monday, December 10th, 2012 AT 12:38 AM
  • Tiny
  • saturntech9
  • Expert
  • 29,290 posts

It looks like you may have a vacuum controled heater control valve look at the hoses going to your heater core see if there is one there?If there is one use a hand vacuum pump to see if it holds vacuum?

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Monday, December 10th, 2012 AT 12:38 AM
  • Tiny
  • saturntech9
  • Expert
  • 29,290 posts

Looks like your blend door is not powered by vacuum.

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Monday, December 10th, 2012 AT 12:40 AM
  • Tiny
  • richardtaylor
  • Member

Really its mechanical?

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Monday, December 10th, 2012 AT 1:45 AM
  • Tiny
  • ASEMaster6371
  • Expert
  • 25,556 posts

Just to add, there is a vacuum elbow behind the throttle body on the pcv line that is common for collapsing and causing the lean codes

Roy

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Monday, December 10th, 2012 AT 1:50 AM

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