B113

Code B113:

Outside Temp Sensor Circuit:

CIRCUIT DESCRIPTION:

The in-car temperature sensor is a thermistor that senses cabin (interior) temperature for the BCM. The BCM applies a voltage on CKT 734 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 B113 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 to ground circuit). During the time the failure is present, a substitute temperature reading will be implemented to allow continued operation of the climate control system. The in-car temperature reading BD25 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 code B113 is set with code B115, check for an intermittent open in circuit 736 between splice S2 and the IP to dash transition block. If an intermittent Code B113 is being set, check the B113 snap data value for in-car temperature, BD25. If the BD25 value is under -34°C, the code was caused by an open in circuit 734, circuit 736, or the in-car temp sensor. If the BD25 value is over 85°C, the code was caused by a short to ground on circuit 734 or a shorted in-car temp sensor. Manipulate the related wiring while observing BCM data BD25. 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 value displayed by BD25 is not reasonably close to the actual temperature of the air at the sensor, check for proper terminal contact or replace the sensor.