B115

Code B115:

Outside Temp Sensor Circuit:

CIRCUIT DESCRIPTION:

The sunload sensor is a thermistor that senses the intensity of the sunlight hitting the car. The BCM applies a voltage on CKT 590 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 B115 will set if the outside temperature sensor has not failed, outside temperature is above 0°C and the signal voltage indicates less than -34°C (open circuit) or over 85°C (shorted circuit). During the time the failure is present, the BCM will disregard the sunload temperature reading for climate control operation. The sunload temperature reading BD32 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 an intermittent Code B115 is being set, check the B115 snap data value for sunload temperature, BD32. If the BD32 value is under -34°C, the code was caused by an open in circuit 590, circuit 736, or the sunload temp sensor. If the BD32 value is over 85°C, the code was caused by a short to ground on circuit 590 or a shorted sunload temp sensor. Manipulate the related wiring while observing BCM data BD32. If the failure is induced, the reading will jump from its normal value to a reading outside the range of -34°C to 85°C.

If the temperature of the sensor, displayed by BD32, is not reasonably close to a corresponding thermometer reading, check for poor terminal contact or replace sensor.