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Test Description

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

  1. 2:  The DTCs listed may set, if there is a concern with the actuator, when a calibration of the actuators is performed.
  2. 10:  This action ensures that the internal fan of the inside air temperature sensor assembly is providing air flow across the internal sensor.
Too Cold in Vehicle

Step Action Values Yes No
Schematic Reference:  HVAC Schematics  
DEFINITION: Temperature can not be adjusted or heating insufficient.
1 Did you perform the HVAC Diagnostic System Check? - Go to Step 2  Go to Diagnostic System Check - HVAC Systems - Automatic 
2 
IMPORTANT: If during this diagnostic procedure the HVAC control module is disconnected a recalibration of actuators must be performed to avoid misdiagnosis.
  1. Recalibrate actuators. Refer to Re-Calibrating Actuators .
  2. Install a scan tool.
  3. Turn ON the ignition, with the engine OFF.
  4. Observe the current DTC list in Heating and Air Conditioning using the scan tool.
Does the scan tool display DTC B0229, B0414, B0434, B3761 or B3764?		 - Go to Diagnostic Trouble Code (DTC) List  Go to Step 3 
3 Place the blower motor switch in each speed position.
Does the blower motor operate in any of the speed positions?		 - Go to Step 4  Go to Blower Motor Inoperative 
4 Does the blower motor operate at the desired speed in each speed position? - Go to Step 5  Go to Blower Motor Malfunction 
5 Does the Too Cold in Vehicle concern occur when heating or defrosting is desired? - Go to Step 6  Go to Step 9 
6
  1. Start the engine.
  2. Place the blower motor switch in the OFF position.
  3. Place the A/C request switch in the OFF position.
Does the A/C compressor operate?		 - Go to HVAC Compressor Clutch Does Not Disengage  Go to Step 7 
7 Perform the Heating Performance Diagnostic. Refer to HEATING SYSTEM PERFORMANCE.
Did you find and correct the condition?		 - Go to Step 26  Go to Step 8 
8 Inspect the heating and cooling system for the following:
  • A low coolant level
  • A loose or worn accessory drive belt
  • A leaking radiator hose or heater hoses
  • A kinked radiator hose or heater hoses
  • A missing radiator cap pressure seal
  • A leaking radiator cap

Did you find and correct the condition?		 - Go to Step 26  Go to Step 9 
9 Inspect the air temperature sensors for the following conditions:
  1. An obstruction to the airflow
  2. Damaged or missing seal to the sensor
  3. Misaligned air ducts
  4. Misaligned sensor

Refer to the following procedures:
Did you find and correct the condition?		 - Go to Step 26  Go to Step 10 
10 
  1. Turn ON the ignition, with the engine OFF.
  2. 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 11  Go to Step 15 
11
  1. Install a scan tool.
  2. Cover the sunload sensor.
  3. Adjust driver side temperature to 22°C (72°F).
  4. With a scan tool, observe the Solar Sensor data parameter in the Primary ECC Data list.
Does the scan tool indicate that the Solar Sensor data parameter is greater than the specified value?		 230 Counts Go to Step 12  Go to Step 20 
12
  1. Uncover the sunload sensor.
  2. Direct a light source at the sunload sensor.
Do the counts change?		 - Go to Step 13  Go to Step 20 
13
  1. Install a thermometer near the inside air temperature sensor.
  2. With a scan tool, observe the Inside Air Temp data parameters in the Primary ECC Data list.
Does the scan tool indicate sensor temperatures are within 3°C (5°F) of the thermometer temperatures?		 - Go to Step 14  Go to Step 17 
14
  1. Turn ON the ignition, with the engine OFF.
  2. Observe the Upper Outlet Temp. and the Lower Outlet Temp. parameter in the Primary ECC Data list.
  3. Turn OFF the ignition.
  4. Measure the resistance of the upper and the lower air temperature sensors. Refer to Sensor Resistance Table (Ambient and Inside Air Temp - ohms)  or Sensor Resistance Table (Upper, Lower and Aux Air Temp - ohms) .
  5. Compare the resistance of the sensor to the count value of the scan tool.
Does the resistance measure near the sensor resistance table value?		 - System OK Go to Step 19 
15 Test the ignition 1 voltage circuit of the inside air temperature sensor for an open or high resistance. Refer to CIRCUIT TESTING and WIRING REPAIRS .
Did you find and correct the condition?		 - Go to Step 26  Go to Step 16 
16 Test the ground circuit of the inside air temperature sensor for an open. Refer to CIRCUIT TESTING and WIRING REPAIRS .
Did you find and correct the condition?		 - Go to Step 26  Go to Step 17 
17 Inspect for poor connections at the harness connector of the inside air temperature sensor. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS and CONNECTOR REPAIRS .
Did you find and correct the condition?		 - Go to Step 26  Go to Step 18 
18 Test the inside air temperature sensor resistance. Refer to the Sensor Resistance Table (Ambient and Inside Air Temp - ohms)  or Sensor Resistance Table (Upper, Lower and Aux Air Temp - ohms) .
Does the resistance measure near the Sensor Resistance Table value?		 - Go to Step 21  Go to Step 22 
19 Inspect for poor connections at the harness connector of the upper and lower air temperature sensors. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS and CONNECTOR REPAIRS .
Did you find and correct the condition?		 - Go to Step 26  Go to Step 23 
20 Inspect for poor connections at the harness connector of the sunload sensor. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS and CONNECTOR REPAIRS .
Did you find and correct the condition?		 - Go to Step 26  Go to Step 24 
21 Inspect for poor connections at the harness connector of the HVAC control module. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS and CONNECTOR REPAIRS .
Did you find and correct the condition?		 - Go to Step 26  Go to Step 25 
22 Replace the inside air temperature sensor. Refer to Inside Air Temperature Sensor Replacement .
Did you complete the replacement?		 - Go to Step 26  -
23 Replace the inside air temperature sensor. Refer to one of the following procedures:
Did you complete the replacement?		 - Go to Step 26  -
24 Replace the sunload sensor. Refer to Sun Load Sensor Replacement .
Did you complete the replacement?		 - Go to Step 26  -
25
IMPORTANT: Perform the recalibration procedure for the HVAC control module.
Replace the HVAC control module. Refer to HVAC Control Module Replacement .Did you complete the replacement?		 - Go to Step 26  -
26 Operate the system in order to verify the repair.
Did you correct the condition?		 - System OK Go to Step 2 
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