GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The Dash Integration Module (DIM) monitors the A/C low side refrigerant temperature through the A/C refrigerant low temperature sensor. When the refrigerant is cold, the sensor resistance and signal voltage are high. When the refrigerant is warm, the sensor resistance and signal voltage are low. The DIM will not request A/C compressor clutch engagement when the refrigerant temperature is low enough to cause the A/C evaporator core to freeze.

Conditions for Running the DTC

The ignition is turned ON.

Conditions for Setting the DTC

The DIM detects the A/C refrigerant low temperature sensor signal circuit is less than 0.09 V (5 counts) or more than 4.90 V (250 counts).

Action Taken When the DTC Sets

The DIM will substitute a default value of 6°C (43°F) to allow operation of the A/C system.

Conditions for Clearing the DTC

    • The DTC will become history if the DIM no longer detects a failure.
    • The history DTC will clear after 40 fault free ignition cycles.
    • The DTC can be cleared with a scan tool.

Test Description

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

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

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

Step

Action

Values

Yes

No

Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

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 Evaporator Temp. parameter in the Dash Integration Module A/C Information data list.

Does the scan tool indicate the Evaporator Temp. parameter is within the specified range?

-37 to +127°C

(-34 to +261°F)

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the A/C refrigerant low temperature sensor.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the Evaporator Temp. parameter.

Does the scan tool indicate the Evaporator Temp. parameter is less than the specified value?

-37°C (-34°F)

Go to Step 4

Go to Step 5

4

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

Does the scan tool indicate the Evaporator Temp. parameter is more than the specified value?

127°C (261°F)

Go to Step 8

Go to Step 6

5

Test the A/C refrigerant low temperature sensor signal circuit of the A/C low 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 A/C refrigerant low temperature sensor signal circuit of the A/C low 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 of the A/C low temperature sensor 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 A/C low 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 DIM. 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 A/C low temperature sensor. Refer to Air Conditioning (A/C) Refrigerant Low Temperature Sensor Replacement in Heating, Ventilation and Air Conditioning.

Did you complete the replacement?

--

Go to Step 12

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11

Important: : Perform the BCM Programming/RPO Configuration procedure in Body Control System for the replacement dash integration module (DIM).

Replace the dash integration module. Refer to Dash Integration Module Replacement in Body Control System.

Did you complete the replacement?

--

Go to Step 12

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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