GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2004 🢒 Regal 🢒 HVAC 🢒 HVAC Systems - Automatic 🢒 DTC B0332, B0333, B0337, or B0338

Circuit Description

The following DTCs are for the temperature sensors monitored by the HVAC control module:

    • B0332 - ambient air temperature sensor
    • B0333 - ambient air temperature sensor
    • B0337 - inside air temperature sensor
    • B0338 - inside air temperature sensor

The HVAC control module monitors the temperature sensors to maintain the comfort level inside of the vehicle. The temperature sensors are a 2 wire negative temperature co-efficient thermistor. The HVAC control module applies 5 volts to internal input resistors that are connected to the signal circuits of the air temperature sensors. The HVAC control module provides the ground to the air temperature sensors through the low reference circuit. The HVAC control module monitors the voltage drop across the air temperature sensors and uses the inputs for automatic control calculations. When the air temperatures are cold, the resistance of the sensors are high and the voltage signals are high. When the air temperatures are hot, the resistance of the sensors are low and the voltage signals are low. The HVAC control module converts the voltage values to count values where 1 V is approximately equal to 51 counts.

Conditions for Running the DTC

The ignition is turned ON.

Conditions for Setting the DTC

The HVAC control module detects the sensor signal circuit is less than 0.09 volt (5 counts) or more than 4.90 volts (250 counts).

Action Taken When the DTC Sets
    • The HVAC control module uses a default value.
    • The HVAC control module will display - - for ambient air temperature when OFF.

Conditions for Clearing the DTC
    • The DTC will become history if the HVAC control module no longer detects a failure.
    • The history DTC will clear after 50 fault-free ignition cycles.
    • The DTC can be cleared by using a scan tool.

Diagnostic Aids

If the condition is 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. The operating range of the sensor is between 0.09-4.90 volts. If the scan tool displays a value between 0-0.08 volt or 4.91-5.0 volts, then the sensor is performing outside of its designed limits.

    2.

  2. Tests for the proper operation of the circuit in the high voltage range.

    3.

  3. Tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to voltage.

  1. Tests the signal circuit for a short to ground.

  1. Test the signal circuit for a short to voltage, a high resistance, or an open.

  1. Tests the low reference circuit for a high resistance or an open.

Step

Action

Value(s)

Yes

No

Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

1

Did you perform the HVAC Diagnostic System Check?

--

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 appropriate temperature sensor parameter in the Heating and Air Conditioning data list.

Does the scan tool indicate that the temperature sensor parameter is within the specified range?

0.09-4.90 V

Go to Diagnostic Aids

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the air temperature sensor.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the appropriate temperature sensor parameter.

Does the scan tool indicate that the temperature sensor parameter is more than the specified value?

4.90 V

Go to Step 4

Go to Step 5

4

  1. Turn OFF the ignition.
  2. Connect a 3-amp fused jumper wire between the air temperature sensor signal circuit and the low reference circuit of the air temperature sensor.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the appropriate temperature sensor parameter.

Does the scan tool indicate that the temperature sensor parameter is less than the specified value?

0.09 V

Go to Step 8

Go to Step 6

5

Test the appropriate signal circuit of the temperature sensor for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 9

6

Test the appropriate signal circuit of the temperature sensor for a short to voltage, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 7

7

Test the low reference circuit for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 9

8

Inspect for poor connections at the harness connector of the temperature sensor. 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 12

Go to Step 10

9

Inspect for poor connections at the harness connector of the HVAC control module. 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 12

Go to Step 11

10

Replace the temperature sensor. Refer to the appropriate replacement procedure:

Did you complete the replacement?

--

Go to Step 12

--

11

Replace the HVAC control module. Refer to HVAC Control Module Replacement .

Did you complete the replacement?

--

Go to Step 12

--

12
  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