Contents Wiring diagrams Section: Automatic HVAC System All sections

HVAC System - Automatic: Diagnosis Chevrolet Aveo I facelift

Conditions for Setting the DTC

This DTC will set if the output of the in-car sensor indicates a probable short circuit or an open in the sensor or the associated wiring harness, or a malfunction of the automatic temperature control (ATC) controller.

StepActionValue(s)YesNo
1Disconnect the in-car sensor connector from the automatic temperature control (ATC) controller. Inspect the wiring from the sensor to the connector and the connector for any signs of damage. Measure the resistance between the in-car sensor connector terminals. Is there any sign of damage in the wiring or connector, or is the resistance measured outside the specified range at 25°C (77°F)?2.2K ohms ± 3%Go to Step 2Go to Step 3
2Repair the damaged wiring or the connector, or replace the in-car sensor as required. Did you find and correct the condition?System OK
3Turn the ignition to ON. Measure the voltage between the two connector terminals on the controller housing. Is the voltage measured greater than or equal to the value specified at 25°C (77°)?2.2 VGo to Step 7Go to Step 4
4Inspect the terminals on the in-car sensor connector. Is any problem found with the connector?Go to Step 5Go to Step 6
5Repair the connector terminals or replace the in-car sensor or ATC controller as required. Did you find and correct the condition?System OK
6Connect the in-car sensor to the controller. Turn the ignition switch to ON. Observe the temperature display area. Does this display indicate the continuing presence of a DTC 1 condition?Go to Step 7System OK
7Replace the ATC controller. Did you complete the replacement?System OK

This DTC will set if the output of the ambient air temperature sensor indicates a probable short circuit or an open in the sensor or the associated wiring harness, or a malfunction of the automatic temperature control (ATC) controller.

StepActionValue(s)YesNo
1Disconnect the ambient air sensor connector from the front bumper harness. Measure the resistance between the ambient air sensor connector terminals. Is the resistance measured equal to the specified range at 25°C (77°F)?2.2K ohms ± 3%Go to Step 5Go to Step 2
2Remove the ambient air sensor from behind the front bumper. Inspect the wiring for any open or short and examine the connector for any damage. Is there a problem with the wiring or the connector?Go to Step 3Go to Step 4
3Repair the problem found in the ambient air sensor wiring or the connector. Did you complete the repair?System OK
4Replace the ambient air sensor Did you complete the replacement?System OK
5Turn the ignition to ON. Measure the voltage between the two terminals in the ambient air sensor connector on the front bumper harness. Is the voltage measured greater than or equal to the specified value?2.2 VGo to Step 7Go to Step 6
6Connect the in-car sensor to the controller. Turn the ignition switch to ON. Observe the temperature display area. Does this display indicate the continuing presence of a DTC 2 condition?Go to Step 8System OK
7Pull the automatic temperature control (ATC) controller from the instrument panel, leaving the wiring harness connected. Measure the voltage between terminals A13 and B8 for the hatchback and between terminals A9 and A20 for the notchback by backprobing the connectors. Is the voltage measured less than or equal to the specified value?2.2 VGo to Step 8Go to Step 9
8Replace the ATC Controller. Did you complete the replacement?System OK
9Test the wiring for the ambient air sensor from the ATC controller, through connectors C209, C208, C202 and C303 for the hatchback or through connectors C207 and C217 for the notchback to the ambient air sensor connector on the front bumper harness. Repair any open or high resistance condition in the wiring or a connector terminal. Did you find and correct the condition?System OK

This DTC code will set if the output of the coolant sensor indicates a probable short circuit or an open in the sensor or the associated wiring harness, or a malfunction of the automatic temperature control (ATC) controller.

StepActionValue(s)YesNo
1Disconnect the coolant temperature sensor connector from the automatic temperature control (ATC) harness. Inspect the wiring from the sensor to the connector and examine the connector for any signs of damage. Measure the resistance between the coolant temperature sensor connector terminals. Is there any sign of damage in the wiring or connector, or is the resistance measured outside the specified range at 25°C (77°F)?2.2K ohms ± 3%Go to Step 2Go to Step 3
2Repair the damaged wiring or the connector, or replace the coolant temperature sensor as required. Did you find and correct the condition?System OK
3Turn the ignition to ON. Measure the voltage between the two coolant temperature sensor connector terminals on the ATC harness. Is the voltage equal to the specified value at 40°C (104°F) and 50°C (122°F)?40°C (104°F)@ 3.7 V 50°C (122°F)@ 2.9 VGo to Step 7Go to Step 4
4Inspect the terminals on the coolant temperature sensor connector. Is any problem found with the connector?Go to Step 5Go to Step 6
5Repair the connector terminals or replace the coolant temperature sensor or ATC controller as required. Did you find and correct the condition?System OK
6Connect the coolant temperature sensor to the ATC harness. Turn the ignition switch to ON. Observe the temperature display area. Does this display indicate the continuing presence of a code 3 condition?Go to Step 9System OK
7Pull the ATC controller from the instrument panel, leaving the wiring harness connected. Measure the voltage between terminals A13 and B9 for hatchback or terminals A16 and A20 for notchback by backprobing the connectors. Is the voltage measured less than or equal to the specified value?40°C (104°F)@ 3.7 V 50°C (122°F)@ 2.9 VGo to Step 9Go to Step 8
8Test the wiring from controller terminals A13 and B9 to the coolant temperature sensor connector terminals on the ATC harness connectors. Repair any open or high resistance found in the wiring or connector terminals. Did you find and correct the condition?System OK
9Replace the ATC controller. Did you complete the replacement?System OK

This code will set if the output of the mix door indicator indicates that the door opening angle is out of range or does not change value when the door should be moving. This would indicate a short circuit or an open in the sensor or the associated wiring harness, a door motor that is not operating, or a malfunction of the automatic temperature control (ATC) controller.

StepActionValue(s)YesNo
1Disconnect the instrument panel (I/P) wiring harness connector from the air mix door (AMD) motor. Use an ohmmeter to measure the resistance between terminals 5 and 7 on the hatchback or 1 and 2 on the notchback on the AMD motor. Does the measured resistance indicate an open or a shorted condition?Open=infinity, short= 0ohmsGo to Step 4Go to Step 2
2Measure the voltage between terminals 2 and 3 on the hatchback or 1 and 2 on the notchback on the AMD motor. Is the resistance measured equal to the specified value?13.5 vGo to Step 3Go to Step 4
3Measure the resistance between terminals 6 and 2 and between terminals 6 and 3 on the AMD motor for the hatchback or measure the voltage between terminals 3 of the AMD and terminal A15 on the ATC for the notchback. Do these measurements equal to the values specified?3000 ohms for the hatchback or 6.0 ± 0.5v for the notchbackGo yo Step 5Go to Step 4
4Replace the AMD motor. Did you complete the replacement?System OK
5Inspect the connector terminals at the AMD motor and the wiring in the ATC harness. Is there a problem with any terminal on either the harness connector or the motor connector or the wiring?Go to Step 6Go to Step 7
6Repair the problem found with a connector terminal or the wiring, or replace the motor as required. Did you find and correct the condition?System OK
7Remove the ATC controller from the instrument panel. Disconnect the harness connectors from the ATC controller. Inspect the connector terminals on the harness connectors and the controller connectors and the harness wiring. Is there a problem with any of these connectors or the wiring?Go to Step 8Go to Step 9
8Repair the problem found with a connector terminal or wiring. Did you complete the repair?System OK
9Measure continuity in the harness between the controller connectors and the following AMD motor connectors: Controller terminal A2 to motor terminal 7 Controller terminal A8 to motor terminal 5 Controller terminal B6 to motor terminal 2 Controller terminal B5 to motor terminal 6 Controller terminal B4 to motor terminal 3 For the hatchback or the following continuity checks for the notchback. Controller terminal B8 to motor terminal 1. Controller terminal A15 to motor terminal 3. Does the continuity equal the specified value?0 ohmsGo to Step 10Go to Step 11
10Repair the continuity problem. Did you complete the repair?System OK
11Connect the AMD motor to the ATC harness. Connect the ATC harness connectors to the controller. Turn the ignition to ON. Use backprobing for voltage measurements. Measure the voltage between ground and terminal B5 at the controller. Is the voltage measured less than or equal to the specified value?4 VGo to Step 12Go to Step 14
12Set the temperature controller to 18°C (64°F). Connect a voltmeter between ground and terminal A8 at the controller. It should display about 12 V. Raise the temperature setting on the controller to 32°C (90°F). Does the voltage equal the specified value?12 V to 0 VGo to Step 13Go to Step 15
13Connect a voltmeter between ground and terminal A2 at the controller. It should display about 12 V. Change the temperature setting to 18°C (64°F). Does the voltage equal the specified value?12 V to 0 VGo to Step 20Go to Step 15
14Inspect the wiring harness and the connector terminals associated with controller terminals B4, B5, and B6, and AMD motor terminals 2, 6, and 3. Repair any problem found. Did you complete the repair?System OK
15Inspect all wiring circuits between the controller and the AMD motor. Is there a problem in the wiring or the connectors?Go to Step 16Go to Step 17
16Repair the condition in the wiring between the ATC controller and the AMD motor. Did you complete the repair?System OK
17Inspect the AMD motor. Is there a problem in the AMD motor?Go to Step 18Go to Step 19
18Replace the AMD motor. Did you complete the replacement?System OK
19Replace the controller. Did you complete the replacement?System OK
20Observe the operation of the air mix door when the temperature setting is changed. Does the door move normally?Go to Step 22Go to Step 21
21Repair or replace the air mix door. Did you find and correct the condition?System OK
22Observe the operation of the AMD motor when the temperature setting is changed. Does the motor operate normally?Go to Step 24Go to Step 23
23Replace the AMD motor. Did you complete the replacement?System OK
24Connect everything and test the system. Does DTC 4 reset?Go to Step 25System OK
25Replace the controller. Did you complete the replacement?System OK

This code will set if the output of the sun sensor indicates a probable short circuit or an open in the sensor or the associated wiring harness, or a malfunction of the automatic temperature control (ATC) controller.

StepActionValue(s)YesNo
1Lift the sun sensor from the top of the dash panel. Secure the ATC harness below the sun sensor connector so it cannot fall through the opening in the top of the dash panel. Disconnect the sun sensor connector from the automatic temperature control (ATC) harness. Inspect the wiring from the sensor to the connector, and examine the connector for any signs of damage. Measure the resistance between the sun sensor connector terminals. Is there any sign of damage in the wiring or connector or does the resistance measured equal the value specified?0 ohmsGo to Step 2Go to Step 3
2Repair the damaged wiring or the connector, or replace the sun sensor as required. Did you find and correct the condition?System OK
3Turn the ignition to ON. Measure the voltage between the 2 sun sensor connector terminals on the ATC harness. Is the voltage measured less than or equal to the specified value?2.5-4.8 VGo to Step 7Go to Step 4
4Inspect the terminals on the sun sensor connector. Is any problem found with the connector?Go to Step 5Go to Step 6
5Repair the connector terminals or replace the sun sensor or ATC controller as required. Did you find and correct the condition?System OK
6Reconnect the sun sensor to the ATC harness. Turn the ignition switch to ON. Observe the temperature display area. Does this display indicate the continuing presence of a code 5 condition?Go to Step 9System OK
7Pull the ATC controller from the instrument panel, leaving the wiring harness connected. Measure the voltage between terminals A13 and B10 for the hatchback or terminals A19 and A20 for the notchback by backprobing the connectors. Is the voltage measured less than or equal to the specified value?2.5-4.8 VGo to Step 9Go to Step 8
8Test the wiring from controller terminals A13 and B10 for the hatchback or terminals A19 and A20 for the notchback to the sun sensor connector terminals on the ATC harness connectors. Repair any open or high resistance found in the wiring or connector terminals. Did you find and correct the condition?System OK
9Replace the ATC controller. Did you complete the replacement?System OK

Symptoms - HVAC Systems - Automatic

IMPORTANTThe following steps must be completed before using the symptom tables.
  1. Perform the «Diagnostic Trouble Code (DTC) List - Vehicle»(ref-300843-S37643368312008101600000) before using the symptom tables in order to verify that all of the following are true: There are no DTCs set. The control module(s) can communicate via the serial data link.
  2. Review the system operation in order to familiarize yourself with the system functions. Refer to «Automatic HVAC Description and Operation»(ref-300850-S01654120532008101600000) .

Visual/Physical Inspection

  1. Inspect for aftermarket devices which could affect the operation of the HVAC System. Refer to «Checking Aftermarket Accessories»(ref-300847-S33638130562008101600000) .
  2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
  3. Verify the A/C compressor clutch turns freely and is not seized.
  4. Verify that the customer is using the correct key to enable personalization and is not inadvertently activating auxiliary HVAC controls.
  5. The following conditions may cause window fogging: Wet carpet or mats High humidity Interior water leak Blocked A/C evaporator drain tube Maximum passenger capacity Blocked body pressure relief valves
  6. Inspect the air distribution system for causes of reduced air flow: Obstructed or dirty passenger compartment air filter, if equipped Blocked or damaged air inlet or outlet vents

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

  1. «Blower Motor Inoperative»(ref-300850-S21468538862008101600000)
  2. «Too Hot in Vehicle»(ref-300850-S28710130922008101600000)
  3. «Too Cold in Vehicle»(ref-300850-S26676623642008101600000)
  4. «Control Head Inoperative»(ref-300850-S21131790272008101600000)