B1325

DTC B1325

Diagnostic Instructions

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

DTC Descriptors

DTC B1325 03
- Device Power Circuit Voltage Below Threshold

DTC B1325 07
- Device Power Circuit Voltage Above Threshold

DTC B1325 4A
- Device Power Circuit Checksum Error - IPC

Diagnostic Fault Information






Circuit/System Description

The control modules on this vehicle monitor the battery voltage through the 12V battery positive (B+) voltage circuits. This vehicle has multiple modules that will set the DTC. For more information on which modules, refer to Diagnostic Trouble Code (DTC) List - Vehicle. Diagnostic Trouble Code Descriptions

Conditions for Running the DTC

* The 12V battery voltage supplied to the control modules is in the range of 7-26 volts.
* The ignition is ON.
* The engine is running.

Conditions for Setting the DTC

B1325 03

The control module detects a 12V system voltage less than a calibrated value, usually 9 volts for 5 seconds.

B1325 07

The control module detects a 12V system voltage greater than a calibrated value, usually 18 volts for 5 seconds.

B1325 4A

The instrument panel cluster (IPC) failed the power on checksum test, either due to low 12V voltage or corrupted memory.

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 can cause this DTC to set.

Circuit/System Verification

1. Measure and record the voltage at the 12V battery terminals with the engine OFF, and again with the engine running. Verify that the 12V battery voltage is 11-17 volts with the engine OFF and with the engine running.

• If the 12V battery voltage is not within the specified range, refer to Charging System Test. Charging System Test

2. Observe the scan tool Battery Positive Voltage parameter in the data list of the module setting the DTC. Verify that the scan tool displays a value that is within 2 volts of the 12V battery voltage recorded in step 1.

• If the scan tool parameter is not within the specified range, refer to Circuit/System Testing.

3. Refer to Diagnostic Aids.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector of the module that set the DTC.
2. Verify that there is less than 1.0 ohm between the ground circuit and the negative 12V battery terminal.

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

3. Ignition ON, verify that a test lamp illuminates between the 12V B+ circuit of the appropriate module and ground.

• If the test lamp does not illuminate, test the 12V B+ circuit for a short to ground or an open/high resistance.

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

Repair Instructions

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