B1446 on 2012-2017 Chevrolet Sonic: OnStar Backup Battery Failure Explained

What's Unique About the 2012-2017 Chevrolet SONIC

For the 2012-2017 Chevrolet Sonic, this code is almost always a straightforward case of the original OnStar backup battery reaching the end of its natural life. These batteries are not rechargeable and have a finite lifespan, so as the first-generation Sonics age, this becomes a very common maintenance item. The repair is simple, but a specific procedure must be followed to avoid damaging the new battery. The VCIM module is consistently located behind the glove box on the Sonic, making access predictable.

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 button/rearview mirror.
• "Service OnStar" message on the Driver Information Center (DIC).
• OnStar system may be non-functional for services requiring the module.
• An OnStar diagnostic report will state there is an issue with the backup battery.

Most Likely Causes

1. Failed OnStar Backup Battery 🔴 High Probability → Shop Vehicle Battery The original backup batteries are non-rechargeable and have a limited service life (typically 3-7 years). As these vehicles have aged, battery failure is now a very common and expected maintenance item.
   How to confirm: Scan for code B1446. The presence of the code along with a red OnStar LED is a near-certain confirmation. The battery itself cannot be easily tested; it is a replacement-only item.
   Typical fix: Replace the OnStar backup battery module. It is crucial to allow the vehicle's Retained Accessory Power (RAP) to time out completely before disconnecting the old module to prevent damaging the new one. This is done by turning the ignition off and opening the driver's door.
   Est. part cost: $40-$95

Rare But Worth Checking

• Faulty Vehicle Communication Interface Module (VCIM): → Shop Telematics Interface Module If replacing the backup battery does not resolve the code, the OnStar module itself may have an internal fault. This is much less common 🎬 Watch: How to replace the VCIM module if the battery fix fails. than simple battery failure.
• Wiring or Connector Issue: Damage to the wiring harness leading to the VCIM or a loose connector could cause this code, but it is unlikely unless other work has recently been performed in that area of the vehicle.

Diagnosis Steps

1. Verify the presence of code B1446 using an OBD-II scanner capable of reading B-codes (Body codes).
2. Confirm the primary symptom: a solid red light on the OnStar indicator.
3. Turn the ignition completely OFF. Open and close the driver's door to cancel Retained Accessory Power (RAP) and wait at least 2-3 minutes for all modules to power down. This is a critical step outlined in TSB PIC4541F.
4. Locate the OnStar/VCIM module. In the 2012-2017 Sonic, this is located behind the glove box. You will need to remove the glove box assembly for access.
🎬 See this video for a quick guide on removing the glove box.
5. Disconnect the main wiring harness from the VCIM.
6. The backup battery is a small black box clipped onto the side of the silver VCIM. Unclip and remove the old backup battery module from the VCIM.
7. Install the new backup battery module by clipping it into place.
8. Reconnect the wiring harness and re-install the module and glove box.
9. Turn the ignition ON. The OnStar light should now be green. Clear the trouble code with the scanner. The code may clear on its own after several successful ignition cycles.

Parts You'll Likely Need

• OnStar Backup Battery (OEM #88861186 (supersedes 19118855, 23117460)) — This is the direct cause of the trouble code. It is a non-rechargeable battery that fails due to age.
  Trusted brands: ACDelco, Genuine GM, Dorman
  OEM price range: $50-$95
  Aftermarket price range: $40-$70

Related Codes That Often Appear With This One

• B1447 — B1447 indicates an open circuit in the backup power source. It is often set along with B1446 and points to the same root cause: a completely dead backup battery. Improperly disconnecting the VCIM can also trigger this code.

Technical Service Bulletins (TSBs) & Recalls

• PIC4541F: Diagnostic Tip - OnStar Back-up Battery Failure. This TSB confirms the cause and provides a critical warning about the replacement procedure.

Platform-Specific Known Issues

• TSB PIC4541F - Critical Replacement Procedure: A Technical Service Bulletin (TSB), PIC4541F, was issued by GM for this exact issue across many models including the Sonic. It highlights that the code is for backup battery failure and explicitly warns technicians not to disconnect power from the module while the ignition or Retained Accessory Power (RAP) is active. Doing so will cause the non-rechargeable backup battery to activate, fully discharge, and be permanently destroyed, requiring another replacement.
• Owner Experience: Straightforward DIY Fix: Owners on forums like Sonic Owners Forum confirm that replacing the OnStar backup battery is a common and simple DIY task. The consensus is that the VCIM module is located behind the glove box, and the battery replacement itself takes only a few minutes once accessed. The main challenge is removing the glove box without breaking any plastic tabs.

Mechanic-Grade Diagnostic Values

• Backup Battery Voltage at VCIM Connector — expected: 12.3-12.9 Volts (on a known-good battery). Failure: Voltage significantly below 12.3V indicates a depleted battery.

Hidden / Shadow Codes Worth Checking

• B1446 03: This is a symptom byte that specifies 'Replace Backup Power Source Voltage Below Threshold'. Its presence confirms the B1446 code is due to a low voltage detection from the battery and not another circuit fault. (see via A professional GM-specific scan tool, such as a Tech 2 or GDS2/MDI.)

Scan Tool Commands That Help

• GM GDS2/MDI: Module Diagnostics -> Telematics Communication Interface Control Module -> ID Information / DTC Information — This function is used to view the specific DTC and, crucially, the symptom byte (like '03') to confirm the exact nature of the fault before replacing parts.
• GM SPS (Service Programming System): VCIM Set-up — This may be required after replacing the VCIM module itself to program it to the vehicle and ensure OnStar services are functional. It is generally not required for just a battery replacement.

Wiring & Ground Locations

• VCIM Connector — Behind the glove box, plugged into the silver OnStar module.. This is the connector where voltage from the backup battery can be tested. On similar GM models, the backup battery supply and ground are at pins 14 and 13.
• G303 — On the left side B-pillar, behind the trim panel.. Wiring diagrams identify this as a ground for the Telematics Communication Interface Control Module (VCIM). A poor connection here could potentially cause communication issues or faulty codes, though it's a rare cause for B1446.
• G302 — Under the center console.. This is another primary ground point for the VCIM. Like G303, a loose or corroded connection here is a rare but possible cause for electrical issues with the OnStar system.

OEM Part Supersession History

• 19118855, 23117460 → 88861186 — Standard part number consolidation and updates by the manufacturer.

Model Year Variations Within This Range

• 2012-2017: While the Sonic received a significant facelift for the 2017 model year, the location of the VCIM (behind the glove box) and the fundamental cause of code B1446 (backup battery failure) did not change. The diagnostic and repair procedure is consistent across the entire 2012-2017 range.