B1317

CIRCUIT DESCRIPTION

The inside air temperature sensor is a thermistor that controls signal voltage to the heater and A/C programmer. The heater and A/C programmer applies voltage on CKT 734. When the sensor is cold, resistance is high therefore the heater and A/C programmer will see high signal voltage at pin D9. As the sensor warms, the resistance becomes less and signal voltage is pulled low through the sensor ground, CKT 407. This signal voltage varies between 5V (open circuit) and 0V (short circuit).

TEST CONDITION(S)

1. Ignition ON.
2. Ambient air temperature reads above -29°C (-20°F).
3. DTC B1310 or B1311 is not set.

ACTION TAKEN

1. A substitute temperature reading of 24°C (75°F) is used to allow continued operation.

TEST DESCRIPTION

1. Scan tool displays inside temperature. Disconnecting the sensor determines if the wiring or sensor is the cause.
2. Test lamp will not light. Test lamp is used to provide a resistance.

NOTES ON INTERMITTENCE

If an intermittent DTC B1317 is being set, connect scan tool, and select data list, open/shorts data and note reading.

Manipulate the wiring while observing scan tool. If failure is induced, the reading will jump. Check for poor terminal contact, and an obstructed or defective sensor.