B1447 on 2013-2017 Chevrolet Trax: OnStar Backup Battery Failure Guide

What's Unique About the 2013-2017 Chevrolet TRAX

The first-generation Chevrolet Trax, like many other GM vehicles from this era built on the Gamma II platform (such as the Buick Encore and Chevrolet Sonic), uses an OnStar module with a non-rechargeable lithium backup battery that has a finite service life. As these vehicles have aged, the failure of this battery is an extremely common and expected maintenance issue. The B1447 code is a direct result of this aging process and almost never points to a more complex system failure on this platform.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Solid red light on the OnStar buttons (typically on the rearview mirror or overhead console)
• "Service OnStar" message on the Driver Information Center (DIC)
• Inability for the OnStar system to function if the main car battery is dead or disconnected
• DTC B1447 stored in the Vehicle Communication Interface Module (VCIM), requires a scan tool capable of reading 'B' (Body) codes.

Most Likely Causes

1. Failed OnStar Backup Battery 🔴 High Probability → Shop Vehicle Battery The original non-rechargeable lithium backup batteries have a typical service life of 4-7 years. For the 2013-2017 model years, most original batteries are now at or beyond their expected lifespan, making this a common maintenance item.
   How to confirm: A professional scan tool confirming B1447 combined with a red OnStar indicator light is a definitive diagnosis. Due to the high failure rate and low cost of the part, replacement is the standard and most efficient diagnostic step.
   Typical fix: Replace the OnStar backup battery. This involves locating the Vehicle Communication Interface Module (VCIM), which on the Trax is most often located under the front passenger seat, opening its access panel, and swapping the old battery for a new one.
   Est. part cost: $40-$70

Rare But Worth Checking

• Wiring Harness or Connector Issue: In very rare cases, the wiring leading to the backup battery could be damaged or the connector could be loose, mimicking a dead battery. This is unlikely unless other service work was recently performed in the area of the OnStar module.

Diagnosis Steps

1. Verify the primary symptom: Is the OnStar status light red? If so, proceed.
2. Use an OBD-II scanner capable of reading Body (B) codes to confirm B1447 is present.
3. CRITICAL: Turn the ignition completely OFF. Open the driver's door to cancel Retained Accessory Power (RAP) and wait for all modules to power down (usually 2-5 minutes) before attempting to service the module.
4. Locate the OnStar/VCIM module. On the 2013-2017 Trax, this is confirmed by owners to be under the front passenger seat. You may need to slide the seat fully forward or back to access it.
5. Disconnect the appropriate connectors from the module as per service instructions. The TSB warns to follow a specific order to prevent damage.
6. The battery is typically in a small plastic housing attached to or next to the main VCIM module. Open the battery compartment and replace the old battery with the new one.
7. Reconnect everything in the reverse order of removal.
8. Start the vehicle. The red OnStar light should turn green after a few moments as the system re-initializes. The code may clear on its own after several drive cycles or can be cleared with a scan tool.

Parts You'll Likely Need

• OnStar Backup Battery (OEM #84549993 (supersedes 88861186, 22704633, 42454411)) — This is the component that fails to set code B1447. It is a wear item with a limited lifespan. The original part number 88861186 has been superseded multiple times.
  Trusted brands: ACDelco (OEM), Dorman (e.g., 926-064 - verify fitment, as this number is sometimes mis-referenced for other parts), Ultralife
  OEM price range: $50-$80
  Aftermarket price range: $40-$60

Related Codes That Often Appear With This One

• B1446 — B1446 indicates the backup battery's voltage is low, while B1447 indicates a complete open circuit (no voltage). They both point to a failed battery, and B1446 may appear first as the battery begins to fail.

Technical Service Bulletins (TSBs) & Recalls

• PIC4541F: Addresses diagnostic tips for OnStar back-up battery failure causing DTC B1446 or B1447 and a red OnStar LED.
• PIT5463B: A related TSB for older models that also discusses B1447 after a software upgrade, reinforcing the fix is to install a new backup battery.

Platform-Specific Known Issues

• GM issued Technical Service Bulletin #PIC4541F for multiple vehicles, including the 2013-2017 Trax, which identifies code B1446 or B1447 and a red OnStar LED as being caused by a backup battery failure. It also provides a critical diagnostic tip: "Do not disconnect the main vehicle battery or remove the OnStar fuse with the ignition key in any position other than OFF. Retained accessory power (RAP) should be allowed to time out or be disabled (simply opening the drivers door should disable RAP) before disconnecting power." Failure to do this can cause the new battery to be instantly and permanently discharged upon connection.

Mechanic-Grade Diagnostic Values

• Backup Battery Supply Voltage — expected: 15.5 volts or greater. Failure: A reading of less than 15.5 volts when testing between the supply voltage circuit and ground.

Hidden / Shadow Codes Worth Checking

• B1447 04: Backup Power Source Open Circuit. This is the most common and specific variant of the code, confirming the VCIM sees a complete lack of voltage from the battery, typical of an aged, failed battery. (see via A professional GM-specific scan tool like a Tech2 or GDS2 is required to view symptom bytes.)
• B1447 07: Backup Power Source Component Protection Timeout Voltage Above Threshold. This is a less common variant that can point to a short to voltage in the wiring or an internal fault in the VCIM's monitoring circuit. (see via A professional GM-specific scan tool like a Tech2 or GDS2 is required to view symptom bytes.)

Scan Tool Commands That Help

• GM GDS2/Tech2: Clear DTCs — After the physical replacement of the backup battery, this command is used to immediately clear the B1447 code from the VCIM's memory. While the code may clear on its own after 50 consecutive malfunction-free ignition cycles, using a scan tool provides immediate confirmation of a successful repair.

Wiring & Ground Locations

• VCIM Connector X1, Pin 14 — On the main Vehicle Communication Interface Module (VCIM) located under the front passenger seat. X1 is one of the primary harness connectors.. Pin 14 is the specific terminal for the 'battery backup supply voltage circuit'. A technician would test for voltage at this pin to verify if power is coming from the battery. A lack of specified voltage here, when the circuit tests good, confirms a dead battery.

Real Owner Repair Stories

• Forum User Discussion (2007 Chevrolet Impala (similar GM OnStar system)) — Red OnStar light and B1447 code present.
  ❌ Tried (didn't work) Initial diagnosis pointed to the common backup battery failure.
  ✅ What actually fixed it The user noted that after replacing the battery, reprogramming of the module was required to clear the code and restore function, with some shops quoting significant labor time for this step. This highlights a potential complication beyond a simple battery swap, though it is not the typical outcome for most Trax/Encore repairs.

OEM Part Supersession History

• 22704633 → 84549993 (and others in between) — Standard part updates and supplier changes over time.
  Heads up: The latest part number, 84549993, is the correct service replacement for the entire 2013-2017 range. Using older, new-old-stock part numbers should be fine, but the latest revision is always recommended.