B1325

DTC B1325

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 Descriptors
DTC B1325 03
- Device Power 1 Circuit Voltage Below Threshold


DTC B1325 07
- Device Power 1 Circuit Voltage Above Threshold




Diagnostic Fault Information






Circuit/System Description

The control modules on this vehicle monitor the battery voltage through the battery positive (B+) voltage circuits. The following control modules will set this DTC:

* Body control module (BCM)
* Instrument panel cluster (IPC)
* Radio
* Sensing and diagnostic module (SDM)



Conditions for Running the DTC

The battery voltage supplied to the control modules is in the range of 7-26 volts.


Conditions for Setting the DTC

B1325 03

The control module detects a system voltage less than 9 volts for 5 seconds.

B1325 07

The control module detects a system voltage greater than 18 volts for 5 seconds.


Action Taken When the DTC Sets

* The control module immediately disables all outputs when an out of range voltage condition has been detected, with the exception of GMLAN and the Run/Crank relay, which are disabled after a 3 minute delay.
* The setting of other DTCs is inhibited.



Conditions for Clearing the DTC

The DTC clears when the malfunction is no longer present.


Diagnostic Aids

* A high or low voltage value in multiple modules indicates a concern in the charging system.
* Overcharging with a battery charger or jump starting can cause this DTC to set.
* This DTC may set if the battery is disconnected for any reason.



Reference Information
Schematic Reference

* Control Module References (Programming and Relearning)
* Ground Distribution Schematics (Ground Distribution Diagrams)

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. Engine running, accessories OFF, measure and record the battery voltage at the battery terminals. The voltage should be between 12.6 and 15.0 volts.

• If not within the specified range, refer to Charging System Test (Charging System Test) .

2. Observe the affected module scan tool Battery Voltage parameter. The reading should be between 12.6 and 15.0 volts.



Circuit/System Testing

1. Ignition OFF, disconnect the harness connector(s) 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. Verify that a test lamp illuminates between the B+ circuit terminals and ground.

• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

4. If all circuits tests normal, replace the appropriate module.



Repair Instructions

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


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