B1446 on 2013-2017 Chevrolet Trax: OnStar Backup Battery Failure Guide

What's Unique About the 2013-2017 Chevrolet TRAX

The 2013-2017 Trax uses a common GM OnStar module (VCIM) shared across many Buick, Chevrolet, and GMC models of the era, most notably its direct platform-mate, the Buick Encore. Code B1446 is a frequent issue on these aging vehicles as the non-rechargeable lithium backup battery simply reaches the end of its 7-10 year service life. Unlike a simple battery swap, this component is a sealed module that must be replaced as a single unit. The failure is so common that GM issued a Technical Service Bulletin (PIC4541F) to address it.

Diagnostic Flowchart

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

Symptoms You May Notice

• Red indicator light on the OnStar button panel in the overhead console or rearview mirror.
• "Service OnStar" message may appear on the driver information center (DIC).
• OnStar system is unable to make a call when the blue button is pressed.
• OnStar advisor may remotely diagnose a backup battery failure if a connection can be established.

Most Likely Causes

1. Failed OnStar Backup Battery 🔴 High Probability → Shop Vehicle Battery The internal battery is a non-rechargeable lithium component with a finite lifespan, typically failing due to age after 5-10 years. This is considered a normal wear-and-tear item as the vehicle ages.
   How to confirm: Scan the vehicle for B-codes. If B1446 is present and the OnStar light is red, the backup battery has almost certainly failed. A GM-specific scan tool may show a symptom byte of '03', which specifically means 'Replace Backup Power Source Voltage Below Threshold'.
   Typical fix: Replace the entire OnStar backup battery module. 🎬 See this walkthrough for replacing the OnStar backup battery This is not just a battery, but a sealed electronic unit. The part may be branded 'Ultralife'. Note that this part is often considered HazMat for shipping, which can increase online purchase costs.
   Est. part cost: $60-$315

Rare But Worth Checking

• Improper Service Procedure:

Diagnosis Steps

1. Confirm the primary symptom: a solid red light on the OnStar indicator.
🎬 Watch: Why your OnStar light is red and how to fix it
2. Use an OBD-II scanner capable of reading B-codes (Body codes) to confirm that B1446 is stored in the VCIM.
3. CRITICAL: Turn the ignition completely off. Open the door to deactivate any retained power and wait at least 10-15 minutes for the Retained Accessory Power (RAP) system to fully shut down before proceeding.
4. Locate the OnStar module. In the Chevy Trax, this is located under the front passenger seat, potentially under the carpet.
5. Inspect the wiring and connector to the module for any visible damage or corrosion, though this is unlikely to be the cause.
6. If the code is present and the battery is original, the diagnosis is conclusive: the backup battery module requires replacement.
7. After replacement, the code should clear automatically once the system powers up and recognizes the valid voltage from the new battery. The OnStar light should turn green after a minute or two.

Parts You'll Likely Need

• Communication Interface Module Battery (OEM #88861186) — This is the official GM replacement part that contains the backup battery. It is the direct and only fix for code B1446. It is a non-rechargeable, sealed unit.
  Trusted brands: ACDelco, GM Genuine Parts, Ultralife (often the manufacturer for the GM part)
  OEM price range: $60-$315

Related Codes That Often Appear With This One

• B1447 — B1447 indicates an open circuit to the backup battery. This can be set along with B1446 if the battery has completely failed or if the module was disconnected improperly during a previous service attempt.

Technical Service Bulletins (TSBs) & Recalls

• PIC4541F: Provides a diagnostic tip for OnStar back-up battery failure, linking it directly to codes B1446 or B1447 and a red OnStar LED. It also warns about accidentally draining the battery during other vehicle service.

Platform-Specific Known Issues

• Per TSB #PIC4541F, technicians are warned to never disconnect the main vehicle battery or remove the OnStar fuse while the ignition is on or Retained Accessory Power (RAP) is active, as this can cause the backup battery to activate and drain itself permanently, requiring replacement.

Mechanic-Grade Diagnostic Values

• OnStar Backup Battery (BUB) Voltage — expected: 12.3-12.9 Volts (as reported by scan tool). Failure: A voltage reading below this range.
• Voltage at VCIM harness connector X1, between terminals 13 and 14 — expected: Greater than 15.5 V (Note: This value from service literature seems unusually high and may be a typo; a healthy 12V battery system should read lower. Proceed with caution.). Failure: Voltage is less than the specified value.

Hidden / Shadow Codes Worth Checking

• B1446 03: Replace Backup Power Source Voltage Below Threshold. This is the most common symptom byte and confirms the battery has failed due to low voltage. (see via GM GDS2 or equivalent professional-grade scan tool capable of reading manufacturer-specific symptom bytes.)
• B1447 04: Backup Power Source Open Circuit. This often sets with B1446 and indicates a completely dead, disconnected, or internally failed battery. (see via GM GDS2 or equivalent professional-grade scan tool.)

Scan Tool Commands That Help

• GM GDS2/SPS: K73 Telematics Communication Interface Control Module: Programming and Setup — This is NOT required for a simple backup battery replacement. This function is used when replacing the entire OnStar/VCIM module, which may be 🎬 Watch: How to replace the VCIM module in a GM vehicle necessary on newer models (e.g. 2017 facelift) or if the module itself has failed.

Wiring & Ground Locations

• VCIM Connector X1 — The main harness connector at the Vehicle Communication Interface Module (OnStar Module), located under the front passenger seat.. This is where the backup battery voltage can be manually tested. Terminals 13 (battery backup supply voltage) and 14 (battery backup low reference) are the specific pins for testing the battery circuit.
• G100 — A ground stud located on the engine compartment, left side of the engine.. While not directly for the VCIM, a TSB for slightly newer Trax models identifies this ground stud as a point where the main engine harness can chafe, causing various electrical issues and codes. Poor grounds can cause unpredictable behavior in multiple modules, so its integrity is worth checking in any complex electrical diagnosis.

Real Owner Repair Stories

• Chevrolet Forum User (2006-2013 Chevrolet Impala (uses same OnStar battery part #88861186)) — Dead OnStar backup battery, red light on mirror.
  ❌ Tried (didn't work) Initial difficulty finding the part and procedure.
  ✅ What actually fixed it Owner purchased the OEM 'Ultralife' battery module (GM P/N 88861186) online for about $55 plus shipping. Located the OnStar unit in the trunk (location differs from Trax) and replaced the battery module in 10 minutes, which resolved the issue.

OEM Part Supersession History

• 19118855, 22704633, 42454411 → 88861186 — Standard part consolidation and revision by the manufacturer.

Model Year Variations Within This Range

• 2017 (facelift models): The 2017 facelifted Trax received a new interior and infotainment system. It may be equipped with a newer generation Telematics module (VCIM) where the backup battery is not a separately serviceable component. On these systems, a battery failure requires replacement of the entire VCIM, which is 'married' to the vehicle's VIN and requires dealer programming (SPS) to function, making it a much more costly repair.