GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2004 🢒 XLR 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 DTC B1420

Circuit Description

The driver door module (DDM) and passenger door module (PDM) check for proper system voltage of 9.0-16.0 volts at least once every 20 milliseconds. When the DDM or PDM detects that system voltage is either below 9.0 volts or above 16.0 volts, a DTC is set and DTC updates are disabled.

DTC B1420 Device Voltage

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
    • Stores DTC B1420 in DDM or PDM memory.
    • DTC updates are disabled.

Conditions for Clearing the DTC
    • The DDM or PDM no longer detects DTC B1420 in DDM or PDM memory, and:
    • The DTC is cleared using a scan tool.

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.
    • Thoroughly inspect the wiring and connectors. An incomplete inspection of the wiring and connectors may result in misdiagnosis causing part replacement with the reappearance of the malfunction. If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Step

Action

Yes

No

Schematic Reference: Power Window Schematics and Door Control Module Schematics

Connector End View Reference: Power Door Systems Connector End Views

1

Did you perform the Vehicle Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

Verify that the vehicle's Starting/Charging system is operating properly.

Is the Starting/Charging system operating properly?

Go to Step 3

Go to Symptoms - Engine Electrical in Engine Electrical

3

Test the appropriate door module ground circuit for a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 5

Go to Step 4

4
  1. Perform the power window reinitialization procedure. Refer to Power Window Reinitialization
  2. Replace the appropriate door module. Refer to Door Control Module Replacement .

Did you complete the replacement?

Go to Step 5

--

5
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK