Fixed and Moveable Windows

DTC B1420

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview)provides an overview of each diagnostic category.



DTC Descriptor
DTC B1420
- Device Voltage




Circuit/System Description

The driver door module (DDM) and passenger door module (PDM) check for proper system voltage of 9-16 volts at least once every 20 milliseconds. When the DDM or PDM detects that system voltage is either below 9 volts or above 16 volts, a DTC is set and DTC updates are disabled.


Conditions for Running the DTC

Battery voltage must be between 9-16 volts.


Conditions for Setting the DTC

The DDM or PDM detects system voltage is below 9 volts or above 16 volts.


Action Taken When the DTC Sets

DTC updates are disabled.


Conditions for Clearing the DTC

* The condition responsible for setting the DTC no longer exists.
* You issue a scan tool CLEAR DTCs command.



Diagnostic Aids

* DTC B1420 may set during vehicle startup if the vehicle system voltage falls bellow 9 volts.
* The Starting/Charging system may be the cause of an intermittent malfunction.



Reference Information
Schematic Reference

Moveable Window Schematics ([1][2]Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Power Windows Description and Operation (Power Windows Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning)


Circuit/System Testing

1. Ignition OFF, disconnect the appropriate door control module harness connector.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 10.

• If the test lamp does not illuminate, test the ground circuit for an open/high resistance.

3. If all circuits test normal, replace the appropriate door control module.



Repair Instructions

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


Control Module References (Programming and Relearning)for DDM or PDM replacement, setup, and programming