GM Service Manual Online
For 1990-2009 cars only

Object Number: 74047  Size: MF
Body Control Module Components
Body Control System Schematics
Handling Electrostatic Discharge Sensitive Parts Notice

Circuit Description

The hatch release switch circuit provides a direct battery input to the BCM when the switch is pressed. This input allows the BCM to detect a hatch release request. If the BCM detects battery voltage on CKT 1576, the BCM will energize the hatch release relay. The BCM monitors the hatch release switch circuit and determines how long voltage has been applied.

Conditions for Setting the DTC

The BCM detects battery voltage on CKT 1576 for longer than 60 seconds.

Action Taken When the DTC Sets

    • Stores a DTC B2573 in the BCM memory.
    • No driver warning message will be displayed for this DTC.

Conditions for Clearing the DTC

    • The BCM no longer detects battery voltage on CKT 1576 for longer than 60 seconds.
    • A history DTC will clear after 50 consecutive ignition cycles if the condition for the malfunction is no longer present.
    • Use the IPC clearing DTCs feature.
    • Use a scan tool.

Diagnostic Aids

    • The following conditions may cause an intermittent malfunction:
       - There is an intermittent short to voltage in CKT 1576.
       - The hatch release switch is shorted to voltage internally or is sticking.
       - The hatch release switch is pressed for longer than 60 seconds.
    • If CKT 1576 is shorted to voltage with the ignition ON, the hatch will release once and then will remain inoperative. If the short occurred when the ignition was turned OFF, the hatch will release as soon as the ignition is turned ON and will then remain inoperative. The BCM will remember the last transition that took place from the hatch release switch and will not release the hatch again until the BCM detects a change from the hatch release switch.
    • If the DTC is a history DTC, the problem may be intermittent. Perform the tests shown while moving related wiring and connectors. This can often cause the malfunction to occur. Refer to Intermittents and Poor Connections .

Test Description

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

  1. This test determines if there is a short to voltage in the hatch release switch circuit.

  2. This test determines if the short to ground is located in CKT 1576 or in the hatch release switch.

DTC B2573 -- Hatch Release Switch Circuit Short to Voltage

Step

Action

Value(s)

Yes

No

1

Were you sent here from the BCM Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Body Control System

2

  1. Turn OFF the ignition switch.
  2. Disconnect the BCM connector C2.
  3. Turn ON the ignition switch.
  4. With a test light connected to ground, probe the BCM connector terminal (harness side) D9.

Is the test light ON?

--

Go to Step 3

Go to Step 5

3

  1. Turn OFF the ignition switch.
  2. Disconnect the hatch release switch connector.
  3. Turn ON the ignition switch.
  4. With a test light connected to ground, probe the BCM connector terminal (harness side) D9.

Is the test light ON?

--

Go to Step 6

Go to Step 7

4

  1. Turn OFF the ignition switch.
  2. Reconnect or install any connectors or components that were disconnected or removed.
  3. Turn ON the ignition switch.
  4. Clear any DTCs.
  5. Wait 60 seconds and check for DTCs.

Does DTC B2573 set as current?

--

Go to Step 8

System OK

5

Check the hatch release switch circuit for an intermittent malfunction. Refer to Diagnostic Aids.

Was a problem found and repaired?

--

Go to Step 9

Go to Step 4

6

Locate and repair the short to voltage in CKT 1576.

Is the circuit repair complete?

--

Go to Step 9

--

7

Replace the hatch release switch. Refer to Rear Compartment Lid Switch Replacement in Body Rear End.

Is the replacement complete?

--

Go to Step 9

--

8

  1. Replace the BCM. Refer to Body Control Module Replacement .
  2. Program the BCM. Refer to Body Control Module (BCM) Programming/RPO Configuration .

Is the replacement complete?

--

Go to Step 9

--

9

  1. Turn OFF the ignition switch.
  2. Reconnect or install any connectors or components that were disconnected or removed.
  3. Turn ON the ignition switch.
  4. Clear any DTCs. Refer to Clearing DTCs .

Is the repair complete?

--

Go to Diagnostic System Check - Body Control System

--