B110

Code B110:

Outside Temp Sensor Circuit:

CIRCUIT DESCRIPTION:

The outside air temperature sensor is a thermistor that controls the signal voltage at the BCM. The BCM applies a voltage on CKT 735 to the sensor. When the sensor is cold, its resistance is high, therefore the BCM will see a high signal voltage. As the sensor warms, its resistance becomes less and the signal voltage is pulled low through the sensor ground, CKT 736. This signal voltage will vary between 5.0 volts (open circuit) and 0 volts (shorted circuit).

Code B110 will set if the ignition is "ON" and the signal voltage indicates less than -35°C (open circuit) or over 58°C (shorted circuit). During the time the failure is present a substitute temperature reading will be implemented to allow continued operation of the climate control system, and the continuous compressor at idle will be disabled. The outside air temperature reading BD26 will however, display the actual sensor reading.

TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.

1. Checks to see if the open circuit reading is due to the circuit or the sensor. If the open circuit reading changes to a shorted circuit reading after jumping the sensor terminals, the BCM and wiring are OK.

2. By applying a ground to various points in the circuits, an open can be isolated by observing whether the parameter display can be changed from the open reading to the shorted reading.

3. Checks to see if the shorted circuit reading is due to the circuit or the sensor. If the shorted circuit reading changes to an open circuit reading after disconnecting the sensor, the BCM and wiring are OK.

NOTE ON INTERMITTENTS:

If the ambient temperature drops below approximately -35°C, this code should be ignored. If B110 is set with any of the following codes, B119, B120, B122, B132, or B440, the most likely cause is an intermittent open in circuit 736. If an intermittent Code B110 is being set, check the B110 snap data value for outside temperature, BD26. If the BD26 value is under -34°C, the code was caused by an open in circuit 735, circuit 736, or the outside temp sensor. If the BD26 value is over 57°C, the code was caused by a short to ground on circuit 735 or a shorted outside temp sensor. Manipulate the related wiring while observing BCM data BD26. If the failure is induced, the reading will jump from its normal value to a reading outside the range of -35°C to 58°C. If the value displayed by BD26 is not reasonably close to the actual temperature of the air at the sensor, check for poor terminal contact or replace sensor.