GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Corvette 🢒 Body 🢒 Doors 🢒 Power Folding Top Does Not Open

Diagnostic Aids
    • Complete the check list, prior to performing the diagnosis:
       - When the folding top control switch is pressed, check for driver information center (DIC) warning messages.
       - Windows are normalized. Refer to Power Windows Description and Operation .
       - Luggage barrier is installed and secured, closing the luggage barrier switch.
       - Vehicle is in PARK or the park brake is applied with manual transmission.
       - Press the ignition to ACCY or RUN, with the engine OFF.
       - Hydraulic fluid bypass valve in the operating position, turned clockwise, located above the pump motor.
       - Operating temperature is normal.
    • When using the scan tool, the folding top cover is referenced as the tonneau.
    • If a repair is made to a signal circuit for a fault to ground, test the component of that circuit for proper operation.
    • Using the scan tool to access the History parameters for the folding top control (FTC) module, will display the last status of the items listed.

Test Description

The number below refers to the step number on the diagnostic table.

  1. This step determines the integrity of valve 1. When commanding the valve on, be careful not to confuse the low audible click from the valve with the louder click from the relay in the FTC module.

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

2

  1. Turn ON the ignition.
  2. Observe the driver information center (DIC) warning messages.
  3. Attempt to operate the power folding top.
  4. If any DIC messages are displayed as a result of top operation, refer to DIC Warning Messages - Roof .

Did you find and correct the condition.

Go to Step 45

Go to Step 3

3

Verify that the power folding top does not open complaint is present.

Does the power folding top open as described in the system description and operation?

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

Go to Step 4

4

During folding top open operation, did top movement stop after the 5 bow raised?

Go to Step 9

Go to Step 5

5

During folding top open operation, did top movement stop after the folding top cover opened?

Go to Step 19

Go to Step 6

6

Did the folding top cover pull down actuator extend to the up position?

Go to Step 7

Go to Folding Top Stowage Compartment Lid Release Inoperative

7

During folding top open operation, after the top was lowered to the stowed position, did the folding top cover close?

Go to Step 8

Go to Step 22

8

Did the folding top cover pull down actuator retract the folding top cover to the closed position?

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

Go to Step 27

9
  1. Install a scan tool.
  2. With a scan tool, observe the 5 Bow Raised Pos. Switch parameter in the Folding Top Module Inputs data list.

Does the 5 Bow Raised Pos. Switch parameter display Active?

Go to Step 12

Go to Step 10

10
  1. Disconnect the 5 bow raised switch connector.
  2. Connect a test lamp from the accessory voltage circuit of the 5 bow raised switch connector to a good ground.

Does the test lamp illuminate?

Go to Step 11

Go to Step 38

11
  1. Connect a 3-amp fused jumper wire between the accessory voltage circuit and the signal circuit of the 5 bow raised switch connector.
  2. With a scan tool, observe the 5 Bow Raised Pos. Switch parameter.

Does the 5 Bow Raised Pos. Switch parameter display Active?

Go to Step 33

Go to Step 28

12

With a scan tool, observe the Top Closed Limit Switch parameter in the Folding Top Module Inputs data list.

Does the Top Closed Limit Switch parameter display Active?

Go to Step 15

Go to Step 13

13
  1. Disconnect the top closed switch connector.
  2. Connect a test lamp from the accessory voltage circuit of the top closed switch connector to a good ground.

Does the test lamp illuminate?

Go to Step 14

Go to Step 38

14
  1. Connect a 3-amp fused jumper wire between the accessory voltage circuit and the signal circuit of the top closed switch connector.
  2. With a scan tool, observe the Top Closed Limit Switch parameter.

Does the Top Closed Limit Switch parameter display Active?

Go to Step 33

Go to Step 28

15

Did the folding top cover unlatch?

Go to Step 16

Go to Folding Top Stowage Compartment Lid Release Inoperative

16

  1. Wait four minutes for the module to release the pressure in the hydraulic system.
  2. Manually open the folding top cover to access the hydraulic fluid bypass valve.
  3. Turn the hydraulic fluid bypass valve counterclockwise to inhibit folding top cover movement.
  4. Navigate the scan tool to Valve 1 in the Roof, Special Functions, FTC data list.
  5. With a scan tool command Valve 1 ON.

Can an audible click be heard from the valve when it is commanded ON?

Go to Step 44

Go to Step 17

17
  1. Disconnect the valve 1 harness connector.
  2. Connect a test lamp from the control circuit of the valve 1 connector to a good ground.
  3. With a scan tool command Valve 1 ON and OFF.

Does the test lamp illuminate when the valve is commanded on?

Go to Step 18

Go to Step 29

18
  1. Connect a test lamp between the control circuit of the valve 1 connector and the ground circuit of the valve 1 connector.
  2. With a scan tool command Valve 1 ON and OFF.

Does the test lamp illuminate when the valve is commanded on?

Go to Step 34

Go to Step 39

19

With a scan tool, observe the Tonneau Open Limit Switch parameter in the Folding Top Module Inputs data list.

Does the Tonneau Open Limit Switch parameter display Active?

Go to Step 36

Go to Step 20

20
  1. Disconnect the folding top cover open switch connector.
  2. Connect a test lamp from the accessory voltage circuit of the folding top cover open switch connector to a good ground.

Does the test lamp illuminate?

Go to Step 21

Go to Step 38

21
  1. Connect a 3-amp fused jumper wire between the supply voltage circuit and the signal circuit of the folding top cover open switch connector.
  2. With a scan tool, observe the Tonneau Open Limit Switch parameter.

Does the Tonneau Open Limit Switch parameter display Active?

Go to Step 35

Go to Step 31

22

With a scan tool, observe the Top Open Limit Switch parameter in the Folding Top Module Inputs data list.

Does the Top Open Limit Switch parameter display Active?

Go to Step 25

Go to Step 23

23
  1. Disconnect the top open switch connector.
  2. Connect a test lamp from the accessory voltage circuit of the top open switch connector to a good ground.

Does the test lamp illuminate?

Go to Step 24

Go to Step 38

24
  1. Connect a 3-amp fused jumper wire between the accessory voltage circuit and the signal circuit of the top open switch connector.
  2. With a scan tool, observe the Top Open Limit Switch parameter.

Does the Top Open Limit Switch parameter display Active?

Go to Step 33

Go to Step 28

25

With a scan tool, observe the Power Pull Down Ajar Status parameter in the Folding Top Module Inputs data list.

Does the Power Pull Down Ajar Status parameter display Ajar?

Go to Step 36

Go to Step 26

26
  1. Disconnect the folding top cover pull down motor harness connector.
  2. Connect a 3-amp fused jumper wire from the folding top cover pull down ajar signal circuit of the connector to a good ground.
  3. With a scan tool, observe the folding top cover Pull Down Ajar parameter

Does the folding top cover Pull Down Ajar parameter display Ajar?

Go to Folding Top Stowage Compartment Lid Release Inoperative

Go to Step 30

27
  1. Disconnect the folding top cover pull down actuator harness connector.
  2. With a scan tool, observe the Power Pull Down Ajar Status parameter in the Folding Top Module Inputs data list.

Does the Power Pull Down Ajar Status parameter display Ajar?

Go to Step 32

Go to Folding Top Stowage Compartment Lid Release Inoperative

28

Test the signal circuit of the inoperative folding top limit or position switch for an open. Refer to Circuit Testing and to Wiring Repairs .

Did you find and correct the condition?

Go to Step 45

Go to Step 36

29

Test the control circuit of the inoperative valve for a short to ground or an open. Refer to Circuit Testing and to Wiring Repairs .

Did you find and correct the condition?

Go to Step 45

Go to Step 36

30

Test the folding top cover pull down ajar signal circuit for an open. Refer to Circuit Testing and to Wiring Repairs .

Did you find and correct the condition?

Go to Step 45

Go to Step 37

31

Test the signal circuit of the folding top cover open switch for an open. Refer to Circuit Testing and to Wiring Repairs .

Did you find and correct the condition?

Go to Step 45

Go to Step 36

32

Test the folding top cover pull down ajar signal circuit for a short to ground. Refer to Circuit Testing and to Wiring Repairs .

Did you find and correct the condition?

Go to Step 45

Go to Step 37

33

Inspect for poor connections at the harness connector of the inoperative limit or position switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 45

Go to Step 40

34

Inspect for poor connections at the harness connector of the inoperative valve. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 45

Go to Step 44

35

Inspect for poor connections at the harness connector of the folding top cover open limit switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 45

Go to Step 41

36

Inspect for poor connections at the harness connector of the folding top control (FTC) module. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs .

Did you find and correct the condition?

Go to Step 45

Go to Step 42

37

Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs .

Did you find and correct the condition?

Go to Step 45

Go to Step 43

38

Repair the open in the accessory voltage circuit of the inoperative limit or position switch. Refer to Wiring Repairs .

Did you find and correct the condition?

Go to Step 45

--

39

Repair the high resistance or open in the ground circuit of the inoperative valve. Refer to Wiring Repairs .

Did you complete the repair?

Go to Step 45

--

40

Replace the inoperative limit or position switch. Refer to Power Folding Top Limit Switches Replacements .

Did you complete the replacement?

Go to Step 45

--

41

Important: The folding top cover open limit switch is an internal part of the folding top cover hydraulic cylinder assembly that is not serviced separately.

Replace the folding top cover open limit switch. Refer to Folding Top Cylinder Replacement .

Did you complete the replacement?

Go to Step 45

--

42

Replace the FTC module. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 45

--

43

Replace the BCM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 45

--

44

Replace the folding top pump, valve, and motor assembly. Refer to Folding Top Pump with Motor Replacement .

Did you complete the replacement?

Go to Step 45

--

45
  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 folding top cover movement.
  6. Press the ignition to ACCY or RUN, with the engine OFF.
  7. Use the scan tool to clear any DTCs.
  8. Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2