GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Corvette 🢒 Body 🢒 Roof 🢒 DTC B3667

Circuit Description

When the power folding top is operated to open or close the folding top, the body control module (BCM) controls the folding top cover latch release operation through the folding top cover release relay control circuit and the tonneau release relay. The relay energizes and applies battery positive voltage to the folding top cover latch actuator. The circuit that generated this diagnostic trouble code (DTC) is the folding top cover release relay control circuit that is wired between the BCM and the tonneau release relay. The BCM applies a 12 volt low current voltage to this circuit to monitor the integrity of this circuit.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B3667 Tonneau Release Circuit

Conditions for Running the DTC
    • The BCM must be powered and cannot have B1327-Battery Voltage Low as an active DTC for this DTC to set.
    • The BCM monitors the voltage of this circuit at all times even when the ignition is in the Off position.
    • The module voltage must be 9-16 volts.

Conditions for Setting the DTC
    • Open detected in the relay control circuit.
    • Short to battery voltage detected in the relay control circuit.
    • Short to ground detected in the relay control circuit.
    • Open in the ground circuit of the tonneau release relay.

Action Taken When the DTC Sets
    • Current and history DTCs are stored.
    • Power folding top operation is disabled until the ignition is cycled OFF/Run ACC.

Conditions for Clearing the DTC

The BCM will clear the current DTC when the short to ground, battery voltage, or open is no longer present.

Diagnostic Aids

When using the scan tool, the folding top cover is referenced as the tonneau.

Test Description

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

  1. This step verifies that the output of the BCM is energizing the tonneau release relay. When the tonneau release relay is commanded ON, listen for a low audible click from the relay. Repeat the commands as necessary.

    2.

  2. This step tests the control circuit of the tonneau release relay for a short to battery voltage. Removing the tonneau release relay will set this DTC causing the BCM to disable output control of the relay until the ignition is cycled OFF/Run ACC.

    3.

  3. This step verifies that the body control module (BCM) is applying battery voltage to the control circuit of the tonneau release relay. Removing the tonneau release relay will set this DTC causing the BCM to disable output control of the relay until the ignition is cycled OFF/Run ACCY. After the test lamp is connected in place of the relay, the ignition must be cycled OFF/Run ACC in order for this step to be a valid test.

  4. This step tests for an open in the ground circuit to the tonneau release relay. Removing the ground from the test lamp opens the control circuit from the BCM, again setting this DTC. After the test lamp is connected, the ignition must again be cycled OFF/Run ACCY in order for this step to be a valid test.

Step

Action

Yes

No

Schematic Reference: Folding Top Schematics

Connector End View Reference: Power Roof Systems Connector End Views

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, navigate to the Tonneau Relay control by making the following selections:
    4. • Vehicle Control Systems
    • Computer/Integrating Systems
    • Special Functions
    • Body Control Module
    • Miscellaneous Tests
  4. Access the tonneau release relay in order to verify operation.
  5. With a scan tool, command the Tonneau Relay ON.

Can a low audible click be heard from the relay?

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 tonneau release relay.
  3. Connect a test lamp from the folding top cover release relay control circuit of the relay connector to a good ground.
  4. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 9

Go to Step 4

4

  1. Cycle the ignition OFF/Run ACCY.
  2. With the test lamp still connected from the folding top cover release relay control circuit of the relay connector to a good ground, command the Tonneau Relay ON.

Does the test lamp illuminate when the relay is commanded ON?

Go to Step 5

Go to Step 6

5

  1. Connect the test lamp between the folding top cover release relay control circuit of the relay connector and the ground circuit of the relay connector.
  2. Cycle the ignition OFF/Run ACC.
  3. With a scan tool, command the Tonneau Relay ON.

Does the test lamp illuminate when the relay is commanded ON?

Go to Step 7

Go to Step 10

6

Test the control circuit of the tonneau release relay for a short to ground or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 8

7

Inspect for poor connections at the harness connector of the tonneau release relay. 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 13

Go to Step 11

8

Inspect for poor connections at the harness connector of the body control module (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 13

Go to Step 12

9

Repair the short to battery voltage in the control circuit of the tonneau release relay . Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 13

--

10

Repair the open in the ground circuit of the tonneau release relay. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 13

--

11

Replace the tonneau release relay.

Did you complete the replacement?

Go to Step 13

--

12

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 13

--

13
  1. Turn OFF the ignition.
  2. Disconnect any jumper wires.
  3. Connect all previously disconnected components.
  4. Replace any open fuses, if necessary.
  5. Turn the bypass valve, clockwise, to allow rear tonneau movement.
  6. Press the ignition to ACCY or RUN, with the engine OFF.
  7. Use the scan tool in order to clear the DTCs.
  8. Operate the vehicle within the Conditions for Running the DTC.

Does the DTC reset?

Go to Step 2

System OK