B1447 on 2013-2017 Cadillac ATS: OnStar Backup Battery Failure Causes and Fixes

What's Unique About the 2013-2017 Cadillac ATS

This is a very common issue across a wide range of GM vehicles from this era, including the Cadillac ATS and its platform mates like the Cadillac CTS and Chevrolet Camaro. The OnStar backup battery is a non-rechargeable lithium battery with a finite service life, typically lasting 3-7 years. Its failure is an expected maintenance item rather than a sign of a deeper electrical problem. The TSB PIC4541F directly addresses this code across dozens of GM models and confirms the cause is almost always the backup battery itself.

Diagnostic Flowchart

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

Symptoms You May Notice

• A solid or flashing red light on the OnStar buttons (typically on the rearview mirror).
• A "Service OnStar" message on the driver information center (DIC).
• Inability to use any OnStar services, including navigation, Wi-Fi, or making a call via the blue button.

Most Likely Causes

1. Failed OnStar Backup Battery 🔴 High Probability → Shop Vehicle Battery The original backup battery is a non-rechargeable lithium battery with a limited chemical lifespan. After several years of service, its voltage naturally depletes, leading to this code. This is considered a normal wear-and-tear item with a typical lifespan of 4-7 years.
   How to confirm: Confirm the presence of code B1447 and a red OnStar indicator light. Given the battery's expected service life, if the vehicle is more than 4-5 years old, the battery is the overwhelming likely cause. Direct replacement is the standard fix.
   Typical fix: Replace the OnStar backup battery. This involves accessing the Vehicle Communication Interface Module (VCIM) in the trunk, unplugging the old battery, and installing a new one.
   Est. part cost: $40-$95

Rare But Worth Checking

• Faulty Vehicle Communication Interface Module (VCIM): → Shop Telematics Interface Module In rare cases, the OnStar module itself can fail, causing it to incorrectly report a battery issue. This is more likely if a new battery does not resolve the code. A related code, U1500, often points to a faulty module. GM also had a customer satisfaction program (#14395) for some 2015 models due to faulty OnStar modules causing battery drain. Replacing the VCIM requires dealer-level programming with the GM Service Programming System (SPS).
• Wiring or Connector Issue: Damage to the wiring leading to the VCIM or corrosion on the battery connector could cause an open circuit. This is unlikely unless the vehicle has had prior interior work or water damage. A poor ground at location G304 or incorrectly routed antenna coax could also cause communication issues with the module.

Diagnosis Steps

1. Verify the trouble code B1447 using an OBD-II scanner capable of reading B-codes (Body codes).
2. Check the status of the OnStar indicator light on the rearview mirror. A red light confirms a system fault.
3. CRITICAL STEP (per TSB PIC4541F): Turn the ignition completely OFF. Allow the Retained Accessory Power (RAP) to time out by waiting a few minutes or by opening and closing the driver's door. Disconnecting power while RAP is active will trigger the new battery's one-time use function and permanently drain it, requiring another replacement.
4. Locate the OnStar/VCIM module. In the 2013-2017 Cadillac ATS, this is located in the trunk, under the rear package shelf.
🎬 Watch this video to see the module location and removal.
5. To access the module, fold down the rear seats. You may need to remove the side sail panels (C-pillar trim) in the back seat area. These typically pop off after removing a 7mm bolt behind a small cover.
6. Pull back the trunk liner/rear package tray to expose the VCIM. It is held in a bracket by 10mm nuts and a 7mm bolt.
7. Disconnect the module's electrical connectors. The backup battery is a small component attached to the VCIM.
8. Replace the old backup battery with a new, compatible part.
9. Reinstall the VCIM module, reconnect all electrical connectors, and reassemble the trim in reverse order.
10. Clear the trouble codes with the scanner.
11. Turn the ignition on and verify the OnStar light turns green after its initial self-check. If the light remains red, the fault may be 'latched' and require a dealer-level scan tool to perform a full reset.

Parts You'll Likely Need

• OnStar Backup Battery (OEM #Verify with dealer by VIN. (e.g., 23117460 for similar Camaro)) — This is the direct cause of code B1447. It is a non-rechargeable battery that fails due to age. The part number from pass 1 (13509943) was found to be incorrect.
  Trusted brands: ACDelco
  OEM price range: $50-$95
  Aftermarket price range: $40-$70

Related Codes That Often Appear With This One

• B1446 — B1446 indicates the backup battery voltage is low, while B1447 indicates an open circuit (no voltage). They often appear together or sequentially as the battery fails completely.

Technical Service Bulletins (TSBs) & Recalls

• PIC4541F: Provides a diagnostic tip for OnStar back-up battery failure causing codes B1446 or B1447 and a red OnStar LED. It covers a wide range of GM vehicles, including the ATS.

Platform-Specific Known Issues

• GM Technical Service Bulletin PIC4541F explicitly identifies DTC B1447 on the 2013-2017 Cadillac ATS as being related to OnStar back-up battery failure.
• The bulletin warns technicians to never disconnect the main vehicle battery or OnStar fuse while the ignition is on or Retained Accessory Power (RAP) is active, as this can permanently discharge a new backup battery, requiring another replacement.
• The VCIM module in the ATS is located in the trunk, under the rear package shelf. Access requires folding the rear seats and removing trim panels, including the C-pillar sail panels.

Scan Tool Commands That Help

• Tech 2 / MDI with GDS2: VCIM Module Information / ID Information — Used to read detailed information from the OnStar module when diagnosing a potential module failure, as opposed to a simple battery failure.
• GM Service Programming System (SPS): Replace and Program Control Module — This function is mandatory after physically replacing the entire Vehicle Communication Interface Module (VCIM). It downloads vehicle-specific software and links the new module to the car's VIN.
• Professional Scan Tool (Dealer-level): Clear Fault Codes / Module Reset — If the red OnStar light remains on after replacing the battery and clearing codes with a basic scanner, the fault may be 'latched.' A more powerful tool may be needed to perform a hard reset of the VCIM. This can occur if the module was previously disconnected physically (e.g., antennas unplugged).

Wiring & Ground Locations

• G304 — Located in the right rear passenger footwell area.. This is a primary ground point for several rear-body components, including the Telematics/OnStar module. A poor connection here could cause intermittent communication issues or fault codes, including B1447, though it's a much rarer cause than battery failure.
• Antenna Coax Splitter — In the wiring path between the roof antenna and the VCIM/Radio.. A TSB notes that if GPS signals are lost, the antenna coax may have been routed incorrectly during a prior repair, bypassing a signal splitter. While not directly causing B1447, damaged or misrouted antenna wiring could be part of a larger issue if multiple OnStar-related faults are present.

Real Owner Repair Stories

• Car Talk Community Forum User (2007 Chevrolet Impala (similar OnStar system)) — The green OnStar light turned red. Pushing the button to run a remote diagnostic confirmed a failing/failed OnStar back-up battery.
  ❌ Tried (didn't work) The user first suspected a connection to a recent main battery replacement where the positive cable was also replaced due to corrosion.
  ✅ What actually fixed it The confirmed fix was the replacement of the OnStar backup battery. The user's research and forum discussion correctly pointed out that disconnecting the main vehicle battery with the key in the ON position can trigger the OnStar backup battery to activate and permanently discharge, which is the likely cause of the failure after the prior service. This aligns perfectly with GM TSB PIC4541F.

When the Usual Fixes Don't Work

• In some cases, replacing the backup battery and clearing the code with a standard scanner may not extinguish the red OnStar light. This does not automatically mean the new battery or the VCIM is faulty. If the vehicle was ever operated with the VCIM physically disconnected (fuse pulled or antennas unplugged, sometimes done for privacy), the module can enter a 'latched' fault state. This state often requires a dealer-level scan tool (like a Tech 2 or MDI) to perform a full module reset, which is a more forceful command than a simple code clear. Before condemning the new battery or the expensive VCIM, a technician should consider if a latched fault is the true cause of the persistent red light.

OEM Part Supersession History

• e.g., 88861186, 13509943 → e.g., 23117460 — Standard part evolution and consolidation across GM platforms.
  Heads up: Part number 23117460 is widely cited for GM vehicles of this era, including platform mates like the Camaro. However, due to minor variations, it is always critical to verify the exact part number with a dealer using the vehicle's VIN before ordering.

Model Year Variations Within This Range

• 2013 only: A TSB for a different issue (power steering) notes that on 2013 ATS models with 4-cylinder automatic transmissions, the main engine ground (G104) was moved from the front to the rear of the engine mid-way through the production year (around Dec 2012). While not the VCIM ground, this highlights that even within the same generation, wiring and component locations can differ between early and late production vehicles, making service manual verification important.