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Ronnie, ASE Certified Technician
Category: Lincoln
Satisfied Customers: 35624
Experience:  35 years as an automotive tech
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I have a code P0174 Lincoln navigator 2003 is this a major

Customer Question

I have a code P0174 for a Lincoln navigator 2003 is this a major repair or not
Also, my heater seems to be blowing cool air when I turn on the heater
Submitted: 1 year ago.
Category: Lincoln
Expert:  Ronnie replied 1 year ago.

Hello and thank you for your question,

The code Po174 is a lean code and the common cause for it to set is usually a leaking PCV supply line. Start with checking the supply line from the engine to where it connects to the PCV valve located in the passenger side valve cover. There are known issues with the hose rotting out at the intake where it connects.

As for the heater, if you warm the engine up and go out under the hood and place your hand on both hoses to the hearer core at the firewall are they both getting nice and hot?

Expert:  Ronnie replied 1 year ago.

If you have had time to check the hoses and found them both to be hot then you are likely dealing with a bad blend door actuator. Post back if that is the case and I will post the steps to replace it. Let me know and we can work from there.