Mountaineer RWD V6-4.0L (2008)
current outside air temperature as measured by the ambient air temperature sensor. When the engine has only been turned off for a short time, or if the
engine is not cold, the instrument cluster (IC) takes a reading of the current temperature and compares the current reading against the last reading at
key off. If the temperature is less than the last key off temperature reading, the instrument cluster (IC) displays the current temperature. If the
temperature is greater than the last key off temperature reading, the instrument cluster (IC) displays the last key off temperature reading until the
ambient air temperature has had time to stabilize with vehicle movement.
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DTC B1255 (Air Temperature External Sensor Circuit Open) - is a continuous and on-demand DTC that sets if the instrument cluster (IC) detects
an open on the outside air temperature sensor input circuit VH407 (YE/GN). If the instrument cluster (IC) detects an open on the outside air
temperature input, the instrument cluster (IC) defaults the display to 23.5°Celsius (75°F).
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DTC B1257 (Air Temperature External Sensor Circuit Short to Ground) - is a continuous and on-demand DTC that sets if the instrument cluster
(IC) detects a short to ground on the outside air temperature sensor input circuit VH407 (YE/GN). If the instrument cluster (IC) detects a short to
ground on the outside air temperature input, the instrument cluster (IC) defaults the display to 23.5°Celsius (75°F).
This pinpoint test is intended to diagnose the following:
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Wiring, terminals or connectors
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Ambient air temperature sensor
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Instrument cluster (IC)
E1-E3
