B1310

CIRCUIT DESCRIPTION

The ambient 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 735. When the sensor is cold the resistance is high, and the heater and A/C programmer will see a high signal voltage at pin C8. When the sensor warms, resistance is reduced and the signal voltage is pulled low through CKT 407. Signal voltage varies from 5V (open circuit) and 0V (short circuit).

TEST CONDITION(S)

1. Ignition ON.

FAILURE CONDITION(S)

If ambient temperature drops below approximately -38°C (-37°F), this DTC should be ignored.

ACTION TAKEN

1. Dashes are displayed on the IPC or CCP (with analog IPC) temperature display.
2. A default value of 15°C (60°F) will be used to allow operation of the A/C system.

TEST DESCRIPTION

1. Scan tool displays ambient temperature. Jumping the harness connector will determine whether the wiring or sensor is the cause.

NOTES ON INTERMITTENCE

If an intermittent DTC B1310 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.