GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2001 🢒 Catera 🢒 HVAC 🢒 HVAC Systems - Automatic 🢒 DTC 011

Circuit Description

The heater and A/C control monitors the inside air temperature via an inside air temperature sensor which is internal to the heater and A/C control. When the air is cold, the sensor resistance and signal voltage are high. When the air is warm, the sensor resistance and signal voltage are low. The heater and A/C control requests A/C compressor clutch engagement and controls the air temperature actuator door positions in order to maintain the selected air temperature on the heater and A/C control.

Conditions for Running the DTC

The ignition is turned ON.

Conditions for Setting the DTC

Inside air temperature sensor signal circuit stays at 4.5 V or higher.

Action Taken When the DTC Sets
    • The heater and A/C control stores a DTC 11 in memory.
    • The system will use a default value.

Conditions for Clearing the DTC
    • The DTC will become history if the heater and A/C control no longer detects a failure.
    • The history DTC will clear after 20 fault free ignition cycles.
    • The DTC can be cleared with a scan tool.

Diagnostic Aids

If condition not present, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Test Description

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

  1. Determines if the malfunction is present.

    2.

  2. The inside air temperature sensor is internal to the heater and A/C control. Replace the heater and A/C control to repair the malfunction.

Step

Action

Value(s)

Yes

No

Schematic Reference: HVAC Schematics

1

Did you perform the HVAC Diagnostic System Check?

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Go to Step 2

Go to Diagnostic System Check - HVAC Systems - Automatic

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the Inside Temp Sensor parameter in the Heating and Air conditioning data list.

Does the scan tool indicate that the Inside Temp Sensor parameter is greater than the specified value?

4.5 V

Go to Step 3

--

3

Inspect for poor connections at the harness connector of the heater and A/C control. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 5

Go to Step 4

4

Important: Perform the recalibration procedure for the heater and A/C control

Replace the heater and A/C control. Refer to HVAC Control Module Replacement .

Did you complete the replacement?

--

Go to Step 5

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5
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK