For 1990-2009 cars

### 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.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 |

1. Disconnect the in-car sensor connector from the automatic temperature control (ATC) controller.
2. Inspect the wiring from the sensor to the connector and the connector for any signs of damage.
3. 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 2

Go to Step 3

2 | Repair the damaged wiring or the connector, or replace the in-car sensor as required. Did you find and correct the condition? | -- | System OK | --
3 |

1. Turn the ignition to ON.
2. 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 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 connector terminals or replace the in-car sensor or ATC controller as required. Did you find and correct the condition? | -- | System OK | --
6 |

1. Connect the in-car sensor to the controller.
2. Turn the ignition switch to ON.
3. Observe the temperature display area.

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

--

Go to Step 7

System OK

7 | Replace the ATC controller. Did you complete the replacement? | -- | System OK | --