B1517

DTC B1517

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 B1517 5A
- Battery Voltage Plausibility Failure




Diagnostic Fault Information






Typical Scan Tool Data










Circuit/System Description

The body control module (BCM) has designated B+ circuits for monitoring vehicle system voltage, fed by the BCM 2 fuse and the SDM or XM/ONSTAR fuse. Fuse 24 in the BCM will either be labeled SDM or XM/ONSTAR, depending on vehicle content. The BCM monitors the system voltage to ensure that the voltage stays within the proper range. Damage to components and incorrect data may occur when the voltage is out of range. The BCM monitors the system voltage over an extended length of time. If the BCM detects the system voltage is outside an expected range for the calibrated length of time, or the BCM battery sense circuits differ by 3 volts, DTC B1517 5A will set. Other modules also monitor system voltage. The system voltage message is sent to the other modules and will default to 12.9 volts if DTC B1517 5A sets..


Conditions for Running the DTC

The DTC will run only if the BCM has power, ground, and the ignition is not in the START mode. This DTC will execute regardless of battery voltage.


Conditions for Setting the DTC

The battery voltage differs by 2 volts on the BCM battery sense circuits for 10 seconds.


Action Taken When the DTC Sets

No indicators are illuminated on the IPC.


Conditions for Clearing the DTC

* The DTC will clear current status when fault is no longer present.
* The history DTC will clear after 50 consecutive ignition cycles have occurred without a malfunction.



Diagnostic Aids

* With any module voltage performance DTC, always perform the Charging System Test (Charging System Test) to ensure that the charging system is functioning properly.
* Inspect the SDM or XM/ONSTAR fuse for an open.



Reference Information
Schematic Reference

* Starting and Charging Schematics (Starting and Charging Schematics)
* Body Control System Schematics (Electrical Diagrams)
* Power Distribution Schematics (Power 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 scan tool BCM Battery Voltage Signal parameter and the Batt. Voltage High Res. parameter. The reading for both parameters should be between 12.6 and 15.0 volts, and should be within 2 volts of each other.



Circuit/System Testing

1. Verify that a test lamp illuminates between the SDM or XM/ONSTAR fuse 24 in the BCM and ground.

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

2. Ignition OFF, disconnect the harness connectors at the BCM.
3. Ignition OFF, test for less than 5 ohms of resistance between the ground circuit terminal E12 X4 and ground.

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

4. Verify that a test lamp illuminates between the B+ circuit terminals listed below and ground.

* Terminal D1 X3
* Terminal D12 X3


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

5. If all circuits tests normal, replace the BCM.



Repair Instructions

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


Control Module References (Programming and Relearning) for BCM replacement, setup, and programming