A011

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The High Side Temperature (HST) sensor is a thermistor that controls a signal voltage to the Air Conditioning Programmer (ACP). The ACP applies a voltage on CKT 732 to the sensor. When the sensor is cold the resistance is high, and the ACP senses high signal voltage at terminal "D14." 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).


TEST CONDITION(S)

1. Ignition "ON."

2. ACP DTC A010 not set.

3. Temperature greater than 30°F.

FAILURE CONDITION(S)

Signal voltage less than -18°C (open circuit) or greater than 179°C (short circuit) calibrated.

On some vehicles this DTC may set intermittently if sensor temperature falls below 30°F. DTC becomes history after sensor temperature increases.

ACTION TAKEN

1. High Cooling Fans operate when A/C compressor operation possible.

NOTES ON FAULT TREE

1. Display AD27, normal operating range is from -18°C to 179°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. Display AD25, AD26, AD27, and AD28. If all display approximately -40, repair open CKT 407 between ACP and C201 terminal "D." If AD27 and AD28 display approximately -40, repair open CKT 407 between C201 terminal "D" and splice S218. If only AD27 displays approximately -40, repair open CKT 407 between splice S218 and HST sensor.

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.