Navigator 2WD V8-5.4L (2007)
E6-E7
Normal Operation
The outside air temperature sensor is mounted on the radiator core support in front of the radiator and A/C condenser and is hardwired to the
instrument cluster through input circuit VH407 (YE/GN) and return circuit VMC29 (YE). The instrument cluster provides a reference voltage to the
ambient air temperature sensor and monitors the change in voltage resulting from changes in resistance as determined by outside air temperature.
When the engine has been off for 2 hours, or the engine temperature is cold, the instrument cluster displays the current outside air temperature as
measured by the ambient air temperature sensor. When the time is less than 2 hours, or if the engine is not cold, the instrument cluster 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 displays the current temperature. If the temperature is greater than the last key off temperature reading, the
instrument cluster displays the last key off temperature reading until the ambient air temperature has had time to stabilize with vehicle movement.
DTC B1255 - is a continuous and on-demand DTC that sets if the instrument cluster detects an open on the outside air temperature sensor input,
circuit VH407 (YE/GN). If the instrument cluster detects an open on the outside air temperature input, the instrument cluster defaults the display to
23.89°C (75°F).
DTC B1257 - is a continuous and on-demand DTC that sets if the instrument cluster detects a short to ground on the outside air temperature sensor
input, circuit VH407 (YE/GN). If the instrument cluster detects a short to ground on the outside air temperature input, the instrument cluster defaults
the display to 23.89°C (75°F).
Possible Causes
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Circuit RH111 (GY/BU) open
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Circuit VH407 (YE/GN) open, short to voltage or ground
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Circuit VMC29 (YE) open or short to voltage
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Outside air temperature sensor
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Instrument cluster
Test F: The Parking Aid On/Off Warning Is Inoperative
PINPOINT TEST F: THE PARKING AID ON/OFF WARNING IS INOPERATIVE
