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 B3971: Folding Top Position SensorDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
B+ - Folding Top Control Module | 1 | 1 | -- | -- |
Top Closed Switch Signal | B1420 | 3, 4 | B3971 | -- |
Top Open Switch Signal | B1420 | 2, 3, 5, 6 | B3971 | -- |
Ground - Folding Top Control Module | -- | 1 | -- | -- |
1. No communication with the FTC module. 2. Power folding top is inoperative 3. Power folding top does not open or complete the top opening procedure. 4. Power folding top does not close or complete the top closing procedure. 5. Folding top stowage compartment lid release inoperative 6. DIC Warning Message | ||||
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
Connector End View Reference
Description and Operation
Power Folding Top Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- 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.
- 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 Open Switch Test. |
| ⇒ | If not the specified value, refer to the Top Closed Switch Test |
Circuit/System Testing
Top Open Switch Test
- Ignition OFF, disconnect the harness connector at the top open position switch.
- Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal B and ground.
- Ignition ON, verify the scan tool Top Open Limit Switch parameter is Inactive.
- 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 all circuits test normal, test or replace the top open position switch.
| ⇒ | 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. |
| ⇒ | 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. |
| ⇒ | 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. |
Top Closed Switch Test
- Ignition OFF, disconnect the harness connector at the top closed position switch.
- Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal B and ground.
- Ignition ON, verify the scan tool Top Closed Limit Switch parameter is Inactive.
- 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 all circuits test normal, test or replace the top closed position switch.
| ⇒ | 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. |
| ⇒ | 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. |
| ⇒ | 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. |
Component Testing
- Ignition OFF, disconnect the harness connector at the appropriate top open or top closed position switch.
- Test for infinite resistance between the signal terminal A and the ignition terminal B with the switch in the open position.
- Test for less than 1 ohm between the signal terminal A and the ignition terminal B with the switch in the closed position.
| ⇒ | If not the specified value, replace the switch |
| ⇒ | If greater than the specified range, replace the switch. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for FTC module and BCM replacement, setup, and programming |
