B1311

CIRCUIT DESCRIPTION
The Outside Air Temperature sensor is a thermistor that controls signal voltage to the Air Conditioning Programmer (ACM). The ACM applies voltage on CKT 735. When the sensor is cold the resistance is high, the ACM 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) to 0V (short circuit).

TEST CONDITION(S)
1. Ignition "ON."

FAILURE CONDITION(S)
If Outside temperature drops below approximately -38°C, this DTC should be ignored.

ACTION TAKEN
1. Display "_______" on Instrument Panel Cluster (IPC) or Climate Control Panel (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.

NOTES ON FAULT TREE
1. Scan tool displays outside temperature. Disconnecting the sensor will determine whether the wiring or sensor is the cause.
2. Test lamp will not light. Test lamp is used to provide a resistance.

NOTES ON INTERMITTENTS
If an intermittent DTC B1311 is being set. Connect scan tool, select ACM 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, obstructed, or defective sensor.