Chevrolet Trax: DTC B1446 OR B1447: Backup power source

Diagnostic Instructions

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

DTC Descriptors

DTC B1446

Replace Backup Power Source Below Minimum Threshold

DTC B1447

Backup Power Source Open Circuit

For symptom byte information refer to Symptom Byte List

Diagnostic Fault Information

Circuit/System Description

The backup power source provides voltage to the telematics communication interface control module , to be able to successfully place a call in the event of a main battery disconnect during a collision event.

Conditions for Running the DTC

B1446 03

• Ignition is ON.
• System voltage is between 9.5 and 15.5 V.
• DTC B1447 is not set.

B1447 04

• Ignition is ON.
• System voltage is between 9.5 and 15.5 V.
• The above conditions are present for greater than 10 s.

Conditions for Setting the DTC

B1446 03

The telematics communication interface control module detects that the backup power source voltage has dropped below the minimum threshold value.

B1447 04

The telematics communication interface control module detects no voltage from the backup power source.

Action Taken When the DTC Sets

B1446 03

The OnStar status LED turns red.

B1447 04

• The OnStar status LED turns red.
• The telematics communication interface control module will be unable to place a call in the event of a main battery disconnect during a collision event.

Conditions for Clearing the DTC

• A current DTC B1446 will clear when the telematics communication interface control module detects the voltage of the backup power source is above the minimum threshold value.
• A current DTC B1447 will clear when the telematics communication interface control module detects voltage from the backup power source.
• A history DTC clears after 50 malfunction-free ignition cycles.

Diagnostic Aids

• Shorting the backup power source positive voltage circuit to the backup power source ground circuit or chassis ground will activate the internal circuit protection of the backup power source, rendering the backup power source inoperative.
• DTC B1447 may set if the K73 Telematics Communication Interface Control Module has been incorrectly disconnected or serviced. When disconnecting the K73 Telematics Communication Interface Control Module , disconnect the harness connector X1 at the K73 Telematics Communication Interface Control Module prior to disconnecting any other harness connectors. This will ensure the backup power source is preserved when voltage is removed from the K73 Telematics Communication Interface Control Module .

Reference Information

Schematic Reference

OnStar/Telematics Schematics (Encore), OnStar/Telematics Schematics (Trax)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - TRAX

Description and Operation

OnStar Description and Operation

Electrical Information Reference

• Testing for Intermittent Conditions and Poor Connections
• Circuit Testing
• Wiring Repairs
• Connector Repairs

Circuit/System Testing

1. Ignition OFF and all vehicle systems OFF, disconnect the X1 harness connector at the K73 Telematics Communication Interface Control Module. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for greater than 9.5 V between the B+ circuit terminal 14 and the low reference circuit terminal 13.

If 9.5 V or less

Test or replace the C3 Telematics Communication Interface Control Module Battery.

If greater than 9.5 V

3. Replace the K73 Telematics Communication Interface Control Module .

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• Communication Interface Module Battery Replacement (Trax), Communication Interface Module Battery Replacement (Encore)
• Control Module References for telematics communication interface control module replacement, programming and setup.

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