B0159

CIRCUIT DESCRIPTION
The HVAC control module monitors the outside ambient air temperature via an ambient air temperature sensor. When the air is cold, the sensor resistance voltage and the signal voltage are high. When the air is warm, the sensor resistance voltage and the signal voltage are low.

CONDITIONS FOR RUNNING THE DTC
The ignition is turned ON.

CONDITIONS FOR SETTING THE DTC
The HVAC control module detects that the signal circuit is out of the range 0.09-5.0 volts.

ACTION TAKEN WHEN THE DTC SETS
A default value will be used for the sensor data by the HVAC control module. The sensor reading, which displays on the scan tool in the HVAC data list, will be the default value.

CONDITIONS FOR CLEARING THE DTC
- The DTC will become history if the HVAC control module no longer detects a condition.
- The history DTC clears after 50 fault free ignition cycles.
- The DTC can be cleared with a scan tool.

DIAGNOSTIC AIDS
If the condition is not present, refer to Testing for Intermittent and Poor Connections in Diagnostic Aids.

TEST DESCRIPTION

Steps 1-11:

The number below refers to the step numbers on the diagnostic table.
2. The scan tool uses a default value. This will not give an accurate reading of the sensor value it an open or a short to ground is detected.