A010

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The Outside Air Temperature (OAT) sensor is a thermistor that controls the signal voltage to the Air Conditioning Programmer (ACP). The ACP applies a voltage on CKT 735 to the sensor. When the sensor is cold the resistance is high and the ACP senses high signal voltage at terminal "D8." As the sensor warms, the resistance becomes less and the signal voltage is pulled low through the sensor ground, CKT 407. Signal voltage varies between 5V (open circuit) and 0V (short circuit).

If the ambient temperature drops below approximately -38°C, this DTC should be ignored.

TEST CONDITION(S)

1. Ignition "ON."

FAILURE CONDITION(S)

Signal voltage less than -39°C (open circuit) or equal to 53°C (short circuit).

ACTION TAKEN

1. Instrument Panel Cluster (IPC) Temperature Display displays

2. ACP uses a substitute temperature value, this allows for continued operation of the HVAC system.

3. ACP data parameter AD26 displays the actual sensor value.

NOTES ON FAULT TREE

Before performing diagnostic, display AD26. If value is not reasonably close to the actual air temperature at the sensor. Check for poor terminal contact or an obstructed sensor.

1. Display AD26, normal operating range is from -38°C to +52°C.

2. Low value indicates an open circuit. Jumper determines whether the wiring or sensor is the cause of the open.

3. High value indicates a short circuit. Removing the sensor determines whether the wiring or sensor is the cause of the short.

4. Open is in the wiring. Jumper determines if the open is in the ground wiring or the sensing wire.

5. Determines if the open is in the sense circuit or at the ACP connection/ACP internal.

6. Determines if the open is in the ground circuit or at the ACP connection/ACP internal.

Display AD25, AD26, AD27, and AD28. If all display approximately -40, repair open CKT 407 between ACP and C2Ol terminal "D." If AD25 and AD26 display approximately -40, repair open CKT 407 between C201 terminal "D" and splice S241. If only AD26 displays approximately -40, repair open CKT 407 between splice S241 and OAT.

NOTES ON INTERMITTENT CONNECTION
If an intermittent DTC is being set, select ACP Snapshot Data for DTC and note value of ACP data parameter. Manipulate the related wiring while observing ACP data parameter. If a failure is induced, the displayed data parameter value will be outside the sensors normal operating range.