GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Vivant 🢒 DTC 🢒 DTC 4

Conditions for Setting the DTC

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

Step

Action

Value(s)

Yes

No

1
  1. Disconnect the instrument panel (I/P) wiring harness connector from the air mix door (AMD) motor.
  2. Use an ohmmeter to measure the resistance between terminals 5 and 7 on the AMD motor.

Does the measured resistance indicate an open or a shorted condition?

--

Go to Step 4

Go to Step 2

2

Measure the resistance between terminals 2 and 3 on the AMD motor.

Does the resistance measure equal to the specified value?

3000 ohms

Go to Step 3

Go to Step 4

3

Measure the resistance between terminals 6 and 2 and between terminals 6 and 3 on the AMD motor.

Do these resistances add up to approximately the value measured between terminals 2 and 3?

3000 ohms

Go yo Step 5

Go to Step 4

4

Replace the AMD motor.

Did you complete the repair?

--

System OK

--

5

Inspect the connector terminals at the AMD motor and the wiring in the FATC harness.

Is there a problem with any terminal on either the harness connector or the motor connector or the wiring?

--

Go to Step 6

Go to Step 7

6

Repair the problem found with a connector terminal or the wiring, or replace the motor as required.

Did you complete the repair?

--

System OK

--

7
  1. Remove the FATC controller from the instrument panel.
  2. Disconnect the harness connectors from the FATC controller.
  3. Examine 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 8

Go to Step 9

8

Repair the problem found with a connector terminal or wiring.

Did you complete the repair?

--

System OK

--

9

Inspect continuity in the harness between the controller connectors and the AMD motor connectors:

    • Controller terminal A15 to motor terminal 7
    • Controller terminal A9 to motor terminal 5
    • Controller terminal B15 to motor terminal 2
    • Controller terminal B16 to motor terminal 6
    • Controller terminal B17 to motor terminal 3

Does the resistance/measure equal the specified value?

0 ohms

Go to Step 10

Go to Step 11

10

Repair the open circuit.

Did you complete the repair?

--

System OK

--

11
  1. Connect the AMD motor to the FATC harness.
  2. Connect the FATC harness connectors to the controller.
  3. Turn ON the ignition.
  4. Measure the voltage between ground and terminal B16 at the controller by backprobing the connector.

Does the voltage measure less than or equal to the specified value?

4 V

Go to Step 12

Go to Step 14

12
  1. Set the temperature controller to LO.
  2. Connect a voltmeter between ground and terminal A9 at the controller. It should display about 12 V.
  3. Raise the temperature setting on the controller to HI.

Does the voltage measure equal to the specified value?

12 V to 0 V

Go to Step 13

Go to Step 15

13
  1. Connect a voltmeter between ground and terminal A15 at the controller. It should display about 12 V.
  2. Change the temperature setting to LO.

Does the voltage measure equal to the specified value?

12 V to 0 V

Go to Step 20

Go to Step 15

14
  1. Inspect the wiring harness and the connector terminals associated with controller terminals B15, B16, and B17, and AMD motor terminals 2, 6, and 3.
  2. Repair any problem found.

Did you complete the repair?

--

System OK

--

15

Inspect all wiring circuits between the controller and the AMD motor.

Is there a problem in the wiring or the connectors?

--

Go to Step 16

Go to Step 17

16

Repair the condition in the wiring between the FATC controller and the AMD motor.

Did you complete the repair?

--

System OK

--

17

Inspect the AMD motor.

Is there a problem in the AMD motor?

--

Go to Step 18

Go to Step 19

18

Replace the AMD motor.

Did you complete the repair?

--

System OK

--

19

Replace the controller.

Did you complete the repair?

--

System OK

--

20

Observe the operation of the air mix door when the temperature setting is changed.

Does the door move normally?

--

Go to Step 22

Go to Step 21

21

Repair or replace the air mix door.

Did you complete the repair?

--

System OK

--

22

Observe the operation of the AMD motor when the temperature setting is changed.

Does the motor operate normally?

--

Go to Step 24

Go to Step 23

23

Replace the AMD motor.

Did you complete the repair?

--

System OK

--

24

Connect everything and test the system.

Does DTC 4 reset?

--

Go to Step 25

System OK

25

Replace the FATC controller.

Did you complete the repair?

--

System OK

--