GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Corvette 🢒 Body 🢒 Body Rear End 🢒 DTC B2573

Circuit Description

The hatch release switch circuit provides a direct battery input to the body control module (BCM) when the switch is pressed. This input allows the BCM to detect a hatch release request. If the BCM detects battery voltage on the rear compartment release switch signal circuit, the BCM will energize the hatch release relay. The BCM monitors the hatch release switch circuit and determines how long voltage has been applied.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B2573 Trunk/Hatch Lamp Control Circuit High

Conditions for Setting the DTC

The BCM detects battery voltage on the rear compartment release switch signal circuit 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 the rear compartment release switch signal circuit 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 instrument panel cluster (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 the rear compartment release switch signal circuit.
       - The hatch release switch is shorted to voltage internally or is sticking.
       - The hatch release switch is pressed for longer than 60 seconds.
    • If the rear compartment release switch signal circuit 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 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. Tests for the normal state of the hatch release switch using a scan tool. The scan tool will display the normal state as INACTIVE, and ACTIVE when the switch is activated.

    2.

  2. Tests if the BCM is able to detect a change in hatch release switch state. The scan tool will display the normal state as INACTIVE, and ACTIVE when the switch is activated.

    3.

  3. Tests for a stuck or shorted hatch release switch. If the hatch release switch is stuck or shorted, the state will change from ACTIVE to INACTIVE when the hatch release switch is disconnected.

    4.

  4. Tests for a short to ground in the hatch release switch signal circuit.

  5. When the BCM is replaced, use a scan tool to perform the BCM RPO Reprogram procedure.

Step

Action

Yes

No

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the Hatch Release Switch parameter in the body control module (BCM) data list.

Does the scan tool display INACTIVE?

Go to Step 3

Go to Step 4

3

  1. Activate the hatch release switch.
  2. With the scan tool, observe the Hatch Release Switch parameter.

Does the Hatch Release Switch parameter change state?

Go to Diagnostic Aids

Go to Step 4

4

  1. Turn OFF the ignition.
  2. Disconnect the hatch release switch.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the Hatch Release Switch parameter.

Does the scan tool display INACTIVE?

Go to Step 7

Go to Step 5

5

Test the signal circuit of the hatch release switch 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 10

Go to Step 6

6

Inspect for poor connections at the harness connector of the BCM. 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 10

Go to Step 8

7

Inspect for poor connections at the harness connector of the hatch release switch. 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 10

Go to Step 9

8

Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 10

--

9

Replace the hatch release switch. Refer to Rear Compartment Lid and Fuel Filler Door Release Switch Replacement .

Did you complete the replacement?

Go to Step 10

--

10
  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