Too Hot in Vehicle. Cadillac CTS

GM Service Manual Online

For 1990-2009 cars only

Makes 🢒 Cadillac 🢒 2003 🢒 CTS - RHD 🢒 HVAC 🢒 HVAC Systems - Automatic 🢒 Too Hot in Vehicle

Test Description

The numbers below refer to the step numbers on the diagnostic table.

The ambient air temperature must be above 3°C (38°F) for this A/C compressor test.

The specified values are from the A/C System Performance Test.

Step

Action

Values

Yes

Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

DEFINITION: The temperature cannot be adjusted, or cooling is insufficient during A/C operation.

Did you perform the HVAC Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - HVAC Systems - Automatic

Important: All DTCs that are set must be diagnosed first unless you were sent to this diagnostic from a specific DTC diagnostic.

Turn ON the ignition, with the engine OFF.
Place the blower motor switch in each speed position.

Does the blower motor operate in any speed position?

Go to Step 3

Go to Blower Motor Inoperative

Does the blower motor operate at the desired speeds?

Go to Step 4

Go to Blower Motor Malfunction

Start the engine.
Place the mode switch in the panel position.
Place the recirculation switch in the ON position.
Observe the recirculation door.
Place the recirculation switch in the OFF position.

Does the recirculation door move from the recirculation position to the outside air position?

Go to Step 5

Go to Air Recirculation Malfunction

Important:

•	If DTC B0157 is set, the A/C compressor clutch will not engage until the code is cleared.

•	The ambient air temperature must be above 3°C (38°F).

Start the engine.
With a scan tool clear any DTCs that are stored in the HVAC control module.
Place the left air temperature switch in the coldest position.
Place the mode switch in the bi-level position.
Place the blower motor on high speed.

Does the A/C compressor operate?

Go to Step 6

Go to HVAC Compressor Clutch Does Not Engage

Perform the A/C system performance test. Refer to Air Conditioning (A/C) System Performance Test in Heating, Ventilation, and Air Conditioning.

Did you find and correct the condition?

Go to Step 24

Go to Step 7

Inspect the inside air temperature sensor for proper installation. Refer to Inside Air Temperature Sensor Replacement .

Did you find and correct the condition?

Go to Step 24

Go to Step 8

Turn ON the ignition with the engine OFF.
Place the mode switch in panel position.
Place the blower motor switch in maximum speed position.
Inspect for airflow through the inside air temperature sensor by placing a 5 cm (2 in) square piece of paper over the sensor air inlet.

Does the paper stay in place?

Go to Step 9

Go to Step 16

Install a thermometer near the inside air temperature sensor.
With a scan tool, observe the Inside Air Temp parameter in the Climate Control Panel data list.

Does the scan tool indicate the sensor temperatures is within 3°C (5°F) of the thermometer temperature?

Go to Step 10

Go to Step 13

Turn OFF the ignition.
Cover the sunload sensor.
Start the engine.
Adjust driver side temperature to 22°C (72°F).
With a scan tool, observe the Driver and Passenger Solar Sensor parameter in the Climate Control Panel Open/Short data list.

Is the Solar Sensor parameter greater than the specified value?

220 Counts

Go to Step 11

Go to Step 18

Uncover the sunload sensor.
Direct a light source at the sunload sensor.
Observe the Driver and Passenger Sunload parameter.

Do the counts change?

Go to Step 12

Go to Step 18

Test the resistance of the ambient air temperature sensor. Refer to Sensor Resistance Table .

Is the resistance near the value in the Sensor Resistance Table?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 14

Test the resistance of the inside air temperature sensor. Refer to Sensor Resistance Table .

Is the resistance near the value in the Sensor Resistance Table?

Go to Step 19

Go to Step 17

Inspect for poor connections at the harness connector of the ambient air temperature sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 24

Go to Step 16

Inspect the aspirator tube for an air leak or obstruction.

Did you find and correct the condition?

Go to Step 24

Inspect for poor connections at the harness connector of the ambient air temperature sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 24

Go to Step 22

Inspect for poor connections at the harness connector of the inside air temperature sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 24

Go to Step 20

Inspect for poor connections at the harness connector of the sunload sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 24

Go to Step 21

Inspect for poor connections at the harness connector of the HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 24

Go to Step 23

Replace the inside air temperature sensor. Refer to Inside Air Temperature Sensor Replacement .

Did you complete the replacement?

Go to Step 24

Replace the sunload sensor. Refer to Sun Load Sensor Replacement .

Did you complete the replacement?

Go to Step 24

Replace the ambient air temperature sensor. Refer to Ambient Air Temperature Sensor Replacement .

Did you complete the replacement?

Go to Step 24