BCM Code B110, Outside Air Temperature Sensor Circuit: Notes

The outside air temperature sensor is a thermistor that controls the signal voltage to BCM. The BCM supplies voltage on circuit No. 735 to sensor. When sensor is cold, its resistance is high, therefore BCM will see a high monitored signal voltage. As sensor warms, its resistance becomes less and signal voltage is pulled low through sensor ground, circuit No. 736. This signal voltage will vary between 5 volts (open circuit) and zero volts (shorted circuit).

Code B110 will set if signal voltage indicates air temperature is less than -34°C (open circuit) or more than 87°C (shorted circuit). During a failure, a substitute temperature reading will be used to allow continued operation of A/C-heater system and compressor will not run continuously at idle.

1. BCM data BD26 will display actual sensor reading. The normal range is from -34°C to 87°C.
2. Checks to see if open circuit reading is due to circuit or sensor. If open circuit reading changes to a shorted circuit reading after jumping sensor terminals, BCM and wiring are okay.
3. By applying a ground to various points in circuits, an open can be isolated by observing whether parameter display can be changed from open reading to shorted reading.
4. Check to see if shorted circuit reading is caused by circuit or sensor. If shorted circuit reading changes to an open circuit reading after disconnecting sensor, BCM and wiring are okay.