Circuit/System Verification

WARNING: This page is about a different car, the 2016 Cadillac ATS. However, it is still accessible from the selected car via links, so may be relevant.

NOTE:

Check for bulletins before proceeding.

Ignition ON.
Verify every applicable scan tool Switch parameter changes when pressing the appropriate switch on the A20 Radio/ HVAC Controls.
- If any parameter does not change
  Replace the A20 Radio/ HVAC Controls.
- If all parameters change
Verify the blower motor operates properly with the blower motor switch in each speed position.
- If the blower motor does not operate in each speed position
  Refer to DTC B0193 .
- If the blower motor operates properly in each speed position
Verify the HVAC doors listed below move when pressing the appropriate switch.
- Driver Temperature
- Passenger Temperature
- Mode
- Recirculation
- If any HVAC door does not move
  Refer to DTC B0223, B0228, B0233, B0408, B0413, B0418, B0423, B1395, or B374A .
- If all HVAC doors move

NOTE:

The refrigerant in this vehicle could be either R-134a or R-1234yf. This will determine the correct special tool to use in step 7. Refer to Refrigerant Recovery and Recharging for correct tool usage.

Install the appropriate ACR Air Conditioning Recharge Service Center.
Verify the high side pressure reading on the Air Conditioning Service Center is within 10% of the scan tool A/C High Side Pressure Sensor parameter.
- If the reading is not within 10%
  Refer to DTC P0531, P0532, or P0533 .
- If the reading is within 10%
Verify the A/C High Side Pressure Sensor parameter is between 269-2929 kPa (39-425 PSI).
- If the reading is not between 269-2929 kPa (39-425 PSI)
  Refer to Air Conditioning (A/C) System Performance Test (LF4, LGX, LTG)Air Conditioning (A/C) System Performance Test (LCV)
- If the reading is between 269-2929 kPa (39-425 PSI)
Verify the scan tool parameters listed below are within 10% of ambient temperature.
- Lower Left Duct Air Temperature Sensor
- Upper Left Duct Air Temperature Sensor
- Lower Right Duct Air Temperature Sensor
- Upper Right Duct Air Temperature Sensor
- A/C Evaporator Temperature Sensor
- If not within 10% of ambient temperature
  Refer to DTC B0173, B0178, B0509, B0514 or B3933 .
- If within 10% of ambient temperature
Verify the scan tool parameters listed below are within 10% of actual conditions.
- Passenger Compartment Humidity
- Passenger Compartment Humidity Sensor Temperature
- Passenger Compartment Windshield Temperature
- If not within 10% of actual conditions
  Refer to DTC B018A, B048C, B048F, or B1395 .
- If within 10% of actual conditions
Engine ON, A/C system ON
Verify cool air flows from the ducts with the temperature control in the coldest position.
- If the air is not cool
1. Verify the Q2 A/C Compressor Clutch is engaged.
  - If the Q2 A/C Compressor Clutch is not engaged, refer to Air Conditioning Compressor Malfunction .
  - If the Q2 A/C Compressor Clutch is engaged, refer to Air Conditioning (A/C) System Performance Test (LF4, LGX, LTG)Air Conditioning (A/C) System Performance Test (LCV) , and DTC B393B .
- If the air is cool
Verify warm air flows from the ducts with the temperature control in the warmest position.
- If the air is not warm
  Refer to Heating Performance Diagnostic .
- If the air is warm
Engine OFF, ignition ON.
Verify the Sunload parameter changes while covering the B10B Ambient Light/Sunload Sensor with a shop towel or other suitable item.
- If the Sunload parameter does not change
  Refer to DTC B0163 (Without UE1) .
- If the Sunload parameter changes
Verify the actual inside air temperature, using a thermometer, is less than 3°C (5°F) difference from the scan tool Inside Passenger Compartment Air Temp. Sensor parameter.
- If greater than a 3°C (5°F) difference
  Refer to DTC B0183 (Without UE1) .
- If less than a 3°C (5°F) difference
All OK.