GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Vivant 🢒 HVAC 🢒 HVAC Systems - Automatic 🢒 DTC 1

Conditions for Setting the DTC

This code 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 full automatic temperature control (FATC) controller.

Step

Action

Values

Yes

No

1
  1. Turn OFF the ignition.
  2. Disconnect the in-car sensor from the full automatic temperature control (FATC) controller.
  3. Examine the wiring from sensor to the connector and the connector for any signs of damage.
  4. Measure the resistance between the in-car sensor connector terminals.

Is there any sign of damage in the wiring or connector, or the resistance outside of the specified value at 20-25°C (68-70°F)?

2600-2100 ohms

Go to Step 2

Go to Step 3

2

Repair the damaged wiring or connector, or replace the in-car sensor.

Did you complete the repair?

--

System OK

--

3
  1. Turn the ignition switch ON.
  2. Measure the voltage between 2 connector terminals on the controller.

Does the voltage measure greater than the specified value?

4 V

Go to Step 7

Go to Step 4

4

Inspect the terminals on the in-car sensor connector.

Is any problem found with the connector?

--

Go to Step 5

Go to Step 6

5

Repair the in-car sensor connector terminals or replace the in-car sensor or FATC controller as required.

Did you complete the repair?

--

System OK

--

6
  1. Reconnect the in-car sensor to the controller.
  2. Turn ON the ignition.
  3. Observe the temperature display screen.

Does the display indicate the continuing presence of a DTC 1 condition?

0 V

Go to Step 7

System OK

7

Replace the FATC controller.

Did you complete the repair?

--

System OK

--