B1327

DTC B1327

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 B1327
- Device Voltage Circuit Low




Diagnostic Fault Information






Circuit/System Description

The control modules on this vehicle monitor system voltage through the battery positive voltage circuits. Damage to components, and incorrect data can occur when the voltage is out of range. This vehicle has multiple modules that will set this DTC. For more information on which modules, refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code Descriptions)


Conditions for Running the DTC

* This DTC shall run only if the module has power, ground, and the ignition is not in START mode.
* This DTC shall execute regardless of the battery voltage.



Conditions for Setting the DTC

* This DTC shall be set as current when the voltage falls below 9 volts for 1.2 seconds
* When the vehicle exits START, the module shall delay checking the voltage for 2 seconds.



Action Taken When the DTC Sets

* A message shall be sent out to notify all other modules of low battery voltage.
* The modules disable the setting of U codes and other DTCs.



Conditions for Clearing the DTC

* The DTC will clear current status when the voltage is greater than 9.5 volts for 1.2 seconds.
* A history DTC will clear after 50 consecutive ignition cycles, if the condition for the malfunction is no longer present.



Reference Information
Schematic Reference

Control Module References (Programming and Relearning)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Charging System Description and Operation (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) for scan tool information.


Circuit/System Verification

1. Ignition OFF, measure the voltage at the battery terminals.
2. Ignition ON, observe the affected module scan tool Battery Positive Voltage parameter. .
3. Verify that battery terminal voltage and Battery Positive Voltage parameter readings do not differ by more than 2 volts.



Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the affected module.
2. Ignition OFF, test for less than 1.0 ohm of resistance between the ground circuit and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, measure between the Battery Positive Voltage circuit and ground. The readings should not differ by more than 2 volts than the battery terminal voltage.

• If greater than the specified value, test the Battery Positive Voltage circuit for a short to ground or an open/high resistance.

4. If the circuit tests normal, replace the affected module.



Repair Instructions

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


Control Module References (Programming and Relearning) for the affected module replacement, setup and programming.