The engine light is on, climate control blows hot air only, are these two problems related? The climate control uses engine vacuum, right?
Apr 26, 2016 at 3:58 PM
codes P0171, P0174
2000 MERCURY SABLE
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P0171 - System too Lean (Bank 1)
P0174 - System too Lean (Bank 2)
On HVAC systems that use vacuum-operated motors, those are usually only for the mode doors. Temperature doors typically aren't vacuum-controlled. If the vacuum hose feeding the heater controls is broken, that could cause enough of a vacuum leak to cause the lean conditions, especially when both sides of the engine are affected. The clue would be you'll most likely only get air from the defroster vents and it won't switch to other functions.
P0174 - System too Lean (Bank 2)
On HVAC systems that use vacuum-operated motors, those are usually only for the mode doors. Temperature doors typically aren't vacuum-controlled. If the vacuum hose feeding the heater controls is broken, that could cause enough of a vacuum leak to cause the lean conditions, especially when both sides of the engine are affected. The clue would be you'll most likely only get air from the defroster vents and it won't switch to other functions.
Apr 26, 2016 at 4:15 PM