GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2008 🢒 Corvette 🢒 Roof 🢒 Folding Top 🢒 DTC B1291

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC B1291: Convertible Top Fifth Bow Position

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

B+ - Folding Top Control Module

1

1

--

--

5 Bow Lowered Switch Signal

B1420

4

B1291

--

5 Bow Raised Switch Signal

B1420

2, 3

B1291

--

Ground - Folding Top Control Module

--

1

--

--

1. No communication with the FTC module.

2. Power folding top does not open or complete the top opening procedure.

3. Power folding top does not close or complete the top closing procedure.

4. DIC Warning Message

Circuit/System Description

The body control module (BCM) supplies ignition voltage to the 5 bow raised and 5 bow lowered switches. The folding top control (FTC) module monitors the signal circuits of these switches to determine the 5 bow raised and 5 bow lowered position of the top. When the top is in the closed position the following definitions of the switches will be true:

    • 5 bow raised switch -- The switch is open and the scan tool parameter should display Inactive.
    • 5 bow lowered switch -- The switch is closed to voltage and the scan tool parameter should display Active.

When the top is in the open/stowed position the following definitions of the switches will be true:

    • 5 bow raised switch -- The switch is closed to voltage and the scan tool parameter should display Active.
    • 5 bow lowered switch -- The switch is open and the scan tool parameter should display Inactive.

Conditions for Running the DTC

The FTC module must be powered and cannot have B1327 or B1328 set as active DTCs for this DTC to set. The battery voltage is between 9-16 volts.

Conditions for Setting the DTC

The FTC module will set B1291 as a current DTC if it senses that both the 5 bow raised and 5 bow lowered switches are active at the same time.

Action Taken When the DTC Sets
    • The FTC module disables all folding top functions.
    • If the condition occurs during operation of the folding top, once the top control switch is released, the FTC module will send a class 2 message to the driver information center (DIC), displaying TOP NOT SECURE.

Conditions for Clearing the DTC
    • This DTC will clear on the current status after the condition for setting the fault is corrected.
    • A history DTC will clear after 50 consecutive ignition cycles without a fault present.

Diagnostic Aids

When the top is in the stowed position, the 5 bow is still in the raised position.

Reference Information

Schematic Reference

Folding Top Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Power Folding Top Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification
  1. When the folding top is in the closed position, the 5 bow raised switch is open and the scan tool 5 Bow Raised Pos. Switch parameter should be Inactive.
    2. ⇒If not the specified value, refer to the 5 Bow Raised Switch Test.
  2. When the folding top is in the open position, the 5 bow lowered switch is open and the scan tool 5 Bow Lowered Pos. Switch parameter should be Inactive.
    3. ⇒If not the specified value, refer to the 5 Bow Lowered Switch Test

Circuit/System Testing

5 Bow Raised Switch Test

  1. Ignition OFF, disconnect the harness connector at the 5 bow raised switch.
  2. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal B and ground.
    3. ⇒If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  3. Ignition ON, verify the scan tool 5 Bow Raised Pos. Switch parameter is Inactive.
    4. ⇒If not the specified value, test the signal circuit for a short to voltage. If the circuit tests normal, replace the FTC module.
  4. Install a 3A fused jumper wire between the ignition circuit terminal B and the signal circuit terminal A. Verify the scan tool 5 Bow Raised Pos. Switch parameter is Active.
    5. ⇒If not specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the FTC module.
  5. If all circuits test normal, test or replace the 5 bow raised switch.

5 Bow Lowered Switch Test

  1. Ignition OFF, disconnect the harness connector at the 5 bow lowered switch.
  2. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal B and ground.
    3. ⇒If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  3. Ignition ON, verify the scan tool 5 Bow Lowered Pos. Switch parameter is Inactive.
    4. ⇒If not the specified value, test the signal circuit for a short to voltage. If the circuit tests normal, replace the FTC module.
  4. Install a 3A fused jumper wire between the ignition circuit terminal B and the signal circuit terminal A. Verify the scan tool 5 Bow Lowered Pos. Switch parameter is Active.
    5. ⇒If not specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the FTC module.
  5. If all circuits test normal, test or replace the 5 bow lowered switch.

Component Testing
  1. Ignition OFF, disconnect the harness connector at the appropriate 5 bow raised or lowered switch.
  2. Test for infinite resistance between the signal terminal A and the ignition terminal B with the switch in the open position.
    3. ⇒If not the specified value, replace the switch
  3. Test for less than 1 ohm between the signal terminal A and the ignition terminal B with the switch in the closed position.
    4. ⇒If greater than the specified range, replace the inoperative switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Folding Top Position Switch Replacement - Number 5 Bow
    •  Control Module References for FTC module and BCM replacement, setup, and programming