B1446

DTC B1446

DTC Descriptor

DTC B1446
- Replace Backup Power Source

Diagnostic Fault Information

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview

Circuit/System Description

The vehicle communication interface module (VCIM) detects the Back-up Battery (BUB) is no longer able to meet the minimum requirements to successfully place a call in the event of a main battery disconnect during a collision event.

Conditions for Running the DTC

* Ignition is in the RUN or ACC position.
* System voltage is between 9.5 and 15.5 volts.
* DTC B1447 is not set.

Conditions for Setting the DTC

The VCIM detects that the back-up battery voltage has dropped below the minimum threshold value.

Action Taken When the DTC Sets

The OnStar(R) status LED turns red.

Conditions for Clearing the DTC

* A current DTC will clear when the VCIM detects the voltage of the back-up battery is above the minimum threshold value.
* A history DTC clears after 50 malfunction-free ignition cycles.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector C1 at the VCIM.
2. Ignition ON, test for 12.3-12.9 volts between the supply voltage circuit terminal 14 and the low reference circuit terminal 13.

• If voltage is not within the specified range, replace the BUB.

3. If all circuits test normal, replace the VCIM.

Repair Instructions

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

* Communication Interface Module Battery Replacement
* Programming and Relearning Programming and Relearning