Mechanics

FORD EXPEDITION HEATER PROBLEM

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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Richardtaylor
December 9, 2012.



I need the exact code numbers and engine size?

Saturntech9
Dec 9, 2012.
5.4L an the code were p0171 an p0174

Tiny
Richardtaylor
Dec 9, 2012.
Have you checked for a vacuum leak yet?Thats where I would start.

Saturntech9
Dec 9, 2012.
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

Tiny
Richardtaylor
Dec 9, 2012.
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?

Saturntech9
Dec 10, 2012.
No that I did think of ill try that thanks for ur help

Tiny
Richardtaylor
Dec 10, 2012.
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?

Saturntech9
Dec 10, 2012.
Looks like your blend door is not powered by vacuum.

Saturntech9
Dec 10, 2012.
Really its mechanical?

Tiny
Richardtaylor
Dec 10, 2012.
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

ASEMaster6371
Dec 10, 2012.
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