B3971
DTC B3971
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
DTC Descriptor
DTC B3971
- Folding Top Position Sensor
Diagnostic Fault Information
Circuit/System Description
The body control module (BCM) supplies ignition voltage to the top open and top closed position switches. The folding top control (FTC) module monitors the signal circuits of these switches to determine the open and closed position of the top.
When the top is in the closed position the following definitions of the limit switches should be true:
* Top closed position switch - The switch is closed to voltage and the scan tool parameter should display Active.
* Top open position 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 can not 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 B3971 as a current DTC if it senses that both the top open and top closed limit 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.
Reference Information
Schematic Reference
Folding Top Schematics ([1][2]Convertible Top)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Power Folding Top Description and Operation (Power Folding Top Description and Operation)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing For Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
1. When the folding top is in the closed position, the top open switch is open and the scan tool Top Open Limit Switch parameter should be Inactive.
• If not the specified value, refer to the Top Open Switch Test.
2. When the folding top is in the open position, the top closed switch is open and the scan tool Top Closed Limit Switch parameter should be Inactive.
• If not the specified value, refer to the Top Closed Switch Test
Circuit/System Testing
Top Open Switch Test
1. Ignition OFF, disconnect the harness connector at the top open position switch.
2. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal B and ground.
• 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 Top Open Limit Switch parameter is Inactive.
• If not the specified value, test the signal circuit terminal A 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 Top Open Limit Switch parameter is Active.
• 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 top open position switch.
Top Closed Switch Test
1. Ignition OFF, disconnect the harness connector at the top closed position switch.
2. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal B and ground.
• 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 Top Closed Limit Switch parameter is Inactive.
• If not the specified value, test the signal circuit terminal A 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 Top Closed Limit Switch parameter is Active.
• 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 top closed position switch.
Component Testing
1. Ignition OFF, disconnect the harness connector at the appropriate top open or top closed position switch.
2. Test for infinite resistance between the signal terminal A and the ignition terminal B with the switch in the open position.
• 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.
• If greater than the specified range, replace the switch.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Folding Top Position Switch Replacement - Number 5 Bow (Folding Top Position Switch Replacement - Number 5 Bow)
* Control Module References (Programming and Relearning) for FTC module and BCM replacement, setup, and programming