Code F11 - A/C High Side Temperature Sensor Circuit: Notes

NOTE: If this code is not displayed during second pass of diagnostic codes, it is an intermittent failure and cannot be diagnosed using this procedure. Refer to notes on intermittents at end of this text.

The A/C high side temperature sensor uses a thermistor to control signal voltage to BCM. The BCM applies voltage on circuit No. 732 to sensor. When sensor is cold, its resistance is high. Therefore BCM will see a high signal voltage. As sensor warms, its resistance becomes less and signal voltage is pulled low through sensor ground, circuit No. 736. This signal voltage will vary between 5 volts (circuit open) and zero volts (circuit shorted).

Code "F11" will set if signal voltage indicates an open circuit (-9°C), or a shorted circuit, (209°C). These conditions can be observed in BCM data display (parameter "P.2.7") as a reading outside the range of -9°C to 209°C.

NOTE: Test numbers refer to test numbers on diagnostic chart.

If shorted circuit reading changes to an open circuit reading after disconnecting sensor, BCM and wiring are okay.
If open circuit reading changes to shorted circuit reading after jumpering sensor terminals, BCM and wiring are okay.
By applying ground to various points in circuits, an open can be isolated by observing whether parameter display can be changed from open reading to shorted reading.