B0161

DTC B0161

CIRCUIT DESCRIPTION




The ambient air temperature sensor provides the HVAC control module software with the temperature of the air outside the vehicle. A reference voltage is supplied to the sensor thermistor and the HVAC control module determines the voltage drop across that device which is proportional to temperature. As the air temperature increases, the resistance decreases. As the air temperature decreases, the resistance increases and the voltage signal increases. The inside air temperature sensor provides the HVAC control module software with the temperature of the air inside the vehicle. A reference voltage is supplied to the sensor thermistor and the HVAC control module determines the voltage drop across that device which is proportional to temperature. As the air temperature increases, the resistance decreases. As the air temperature decreases, the resistance increases and the voltage signal increases.

CONDITIONS FOR RUNNING THE DTC
1. The ignition is in the RUN position.
2. Any of the conditions for setting the DTC are met for 30 seconds.

CONDITIONS FOR SETTING THE DTC

B0160
The HVAC control module detects the ambient air temperature sensor signal circuit is less than 10 counts for more than 30 seconds.

B0161
The HVAC control module detects the ambient air temperature sensor signal circuit is more than 252 counts for more than 30 seconds.

B0165
The HVAC control module detects the inside air temperature sensor signal circuit is less than 10 counts for more than 30 seconds.

B0166
The HVAC control module detects the inside air temperature sensor signal circuit is more than 252 counts for more than 30 seconds.

ACTION TAKEN WHEN THE DTC SETS

B0160 or B0165
The system operates in the maximum cooling mode, except when maximum heating is selected.

B0161 or B0166
The system operates in the maximum heating mode, except when maximum cooling is selected.

CONDITIONS FOR CLEARING THE DTC
- The DTC will become history if the HVAC control module no longer detects the condition that set the DTC.
- The history DTC will clear after 40 fault free ignition cycles.
- The DTC can be cleared with a scan tool.

DIAGNOSTIC AIDS
- For inside air temperature problems check the aspirator hose connection on the HVAC control module.
- If no problem has been found refer to Testing for Intermittent and Poor Connections in Diagnostic Aids.

TEST DESCRIPTION

Steps 1-7:

Steps 8-13:

The numbers below refer to the step numbers on the diagnostic table.
3. Tests for the proper operation of the circuit in the high voltage range. The inside air temperature sensor is located inside the HVAC control module. Testing for the inside air temperature sensor will be done through the HVAC control module connector.
4. Tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens upon performing this test, the signal circuit has a short to voltage.
11. Replacement of the inside air temperature sensor can only be done by replacing the HVAC control module.