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DTC B1420

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 B1420
- Device Voltage

Diagnostic Fault Information





Circuit/System Description

The body control module (BCM) applies battery voltage to the accessory voltage circuit when the ignition is in the ON position. The folding top control (FTC) module monitors this circuit at least once every 300 milliseconds to determine if voltage is supplied to the following folding top switches:

* Top open switch
* Top closed switch
* Luggage barrier switch
* Folding top cover open switch
* 5 bow raised switch
* 5 bow lowered switch
* Header latched switch

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

* If the FTC module detects the accessory voltage dropping below 3 volts.
* The power mode is either in Accessory, RUN, Rap or Crank.

Action Taken When the DTC Sets

* Stores a current and history DTC B1420 in the FTC module.
* The folding top operation is suspended.
* 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 ()
Connector End View Reference

Component Connector End Views (Connector Views)
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 Testing

1. Ignition OFF, disconnect the X2 harness connector at the FTC module.
2. Ignition ON, test for B+ between the ignition circuit terminal D11 and ground.

• If less than the specified value, test the ignition circuit for a short to ground or an open/high resistance. If all circuits test normal, replace the BCM.

3. If all circuits test normal, replace the FTC module.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

Control Module References (Programming and Relearning) for FTC module and BCM replacement, setup, and programming