B3060 on 2016-2020 Cadillac CT6: Security System Faults and Fixes

What's Unique About the 2016-2020 Cadillac CT6

The Cadillac CT6 features a sophisticated passive entry and keyless start system that operates on a 125 kHz frequency for passive entry and 433MHz for remote functions. While convenient, this system is sensitive to communication errors between the key fob and the vehicle's various control modules. Unlike older, simpler systems, a fix for the CT6 often requires not just a mechanical key but a correctly programmed electronic handshake. Issues can arise from something as simple as radio frequency (RF) interference from other devices on your keychain or in the vicinity, a problem GM has noted extensively in technical service bulletin PIC5650M. The bulletin warns that aftermarket LED lights, phone chargers, and even toll passes can cause RFI, leading to this code.

Diagnostic Flowchart

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

Symptoms You May Notice

• Engine will not crank (no-crank, no-start)
• Engine starts but stalls immediately
• Security indicator light is illuminated or flashing on the dashboard
• "No Fob Detected" message on the driver information center
• Passive entry (keyless door unlocking) does not work
• Remote Keyless Entry (RKE) functions have poor range or are inoperative

Most Likely Causes

1. Weak or Dead Key Fob Battery 🔴 High Probability → Shop Vehicle Battery The passive entry system requires a constant low-power signal from the fob, which can drain the battery over time. The system is sensitive and a slightly weak battery may fail to communicate properly.
   How to confirm: Try the spare key fob. If the spare key works, the battery in the primary key is the most likely culprit. A 'low key battery' message may also appear on the dash. Alternatively, place the suspect fob in the transmitter pocket in the center console; if the car starts, the battery is too weak for wireless communication but strong enough for direct contact reading.
   Typical fix: Replace the CR2032 battery in the key fob. 🎬 Watch: A quick guide to replacing your CT6 key fob battery.
   Est. part cost: $2-$10
2. Radio Frequency (RF) Interference 🟡 Medium Probability As noted in GM TSB PIC5650M, the CT6's sensitive receivers can be 'jammed' by other RFID devices. Common culprits include other car keys, office access cards, toll passes, aftermarket LED lighting, and even certain USB phone chargers.
   How to confirm: Remove all other keys and electronic devices from the keychain and from inside the vehicle. Try starting the vehicle with only the CT6 key fob present. Also, try starting the car in a different location to rule out environmental interference.
   Typical fix: Isolate the key fob from other electronic devices. Remove problematic aftermarket accessories.
   Est. part cost: $0
3. Faulty Key Fob 🟡 Medium Probability → Shop Keyless Entry Transmitter Internal components of the key fob can fail from being dropped or from age, causing the transponder chip to malfunction.
   How to confirm: If a new battery and removing RF interference sources don't work, but the spare key does, the original key fob is likely faulty.
   Typical fix: Replace and program a new key fob. 🎬 See how to program a new smart key remote yourself. This must be done by a dealer or a qualified automotive locksmith with tools like the Autel KM100 or similar.
   Est. part cost: $150-$400
4. Immobilizer/BCM Programming Issue ⚪ Low Probability A glitch in the Body Control Module (BCM) or Keyless Entry Control Module can cause it to lose synchronization with the programmed keys. This can sometimes be triggered by a low vehicle battery or a failed software update.
   How to confirm: This requires a professional scan tool to check the status of the security modules and confirm if they are communicating correctly with the keys. A dealer will use GM's GDS2 software.
   Typical fix: Reprogram the keys to the vehicle's immobilizer system. In rare cases, the BCM itself may need to be reprogrammed or replaced. A replacement BCM for a CT6 can cost several hundred dollars plus programming.
   Est. part cost: $100-$1000+

Rare But Worth Checking

• Low Vehicle Battery Voltage: → Shop Vehicle Battery A weak main vehicle battery can cause various electronic modules, including the anti-theft system, to malfunction and set false codes. If you're experiencing other electrical gremlins, check the vehicle battery first.
• Faulty Keyless Entry Antenna: → Shop Antenna The vehicle has several antennas to detect the key fob. If one of these fails, the car may not detect the key when you try to start it, leading to this code. Diagnosis requires a scan tool to check antenna status and may set antenna-specific codes like B3119 or B3121.
• Aftermarket Window Tint: TSB PIC5650M specifically mentions that certain types of aftermarket window tints, particularly those with metallic elements, can interfere with RF signals and cause passive entry/start issues.

Diagnosis Steps

1. Check for a security light on the dashboard. This confirms an anti-theft issue.
2. Try the spare key fob. If it works, the problem is with your primary key or its battery.
3. Replace the battery (CR2032) in the non-working key fob.
4. Remove all other keys, fobs, and RFID cards from the keychain and from inside the car. Also unplug any aftermarket chargers or devices and try again.
5. If the car still won't start, try placing the key fob in the designated transmitter pocket. For the CT6, this is located inside the center console storage area. Slide the fob into the pocket with the buttons facing the rear of the car and attempt to start the vehicle. 🎬 Watch this video to fix the 'No Fob Detected' error. This uses a direct antenna to read the fob, bypassing potential interference.
6. Check the main vehicle battery's state of charge and overall health. A voltage below 12.4V can cause electronic issues.
7. If all else fails, the vehicle needs to be scanned with a professional tool that can read GM body codes (like a Tech 2 or GDS2) to check the status of the immobilizer system, key programming, and look for other related DTCs.

Parts You'll Likely Need

• Key Fob Battery (OEM #CR2032) — This is the most common and cheapest fix. The key fob's signal weakens as the battery dies, causing communication failure.
  Trusted brands: Energizer, Duracell, Panasonic
  OEM price range: $5-$10
  Aftermarket price range: $2-$5
• Keyless Entry Remote (Key Fob) (OEM #13510236 (Other compatible P/Ns: 13598540, 13598538, 13594022, 13510255)) — If the fob's internal transponder has failed, the entire unit must be replaced and programmed. The FCC ID for this remote is HYQ2EB.
  Trusted brands: ACDelco (OEM)
  OEM price range: $150-$300
  Aftermarket price range: $70-$150

Related Codes That Often Appear With This One

• B3055 — Relates to the key transponder. Often set together with B3060 when there's a key recognition issue.
• B3935 — Transponder Authentication Error. This code is also directly related to the immobilizer system failing to authenticate the key.
• C0750, C0755, C0760, C0765, C0775 — These are tire pressure monitor sensor codes. The TSB PIC5650M lists them alongside B3060, suggesting a potential link in how the vehicle's remote functions are processed, possibly through a shared receiver (RCDLR) or interference affecting both systems.

Technical Service Bulletins (TSBs) & Recalls

• PIC5650M: Addresses intermittent no crank, no start, or start stall concerns with the security light on. It lists DTC B3060

Platform-Specific Known Issues

• A GM Technical Service Bulletin (TSB), #PIC5650M, directly addresses an intermittent no-crank or start-stall condition with the security light on, specifically citing DTC B3060. It points to potential issues with Radio Frequency Interference (RFI) from a wide range of sources including aftermarket LED lights, phone chargers, and other keys. The bulletin strongly advises against replacing any parts until RFI has been ruled out.
• Some owners on forums like Reddit have noted various electrical issues on the CT6 platform, reinforcing the idea that the vehicle's complex electronics can be sensitive. While no specific forum thread details a B3060 repair from start to finish, general discussions point to transmission and electronic module problems as known quirks of the car.

Mechanic-Grade Diagnostic Values

• Keyless Entry Antenna Low Reference Circuit to Ground — expected: Less than 2 Ω. Failure: 2 Ω or greater indicates an open or high resistance in the circuit.
• Keyless Entry Antenna Signal Circuit to Ground — expected: Infinite resistance (OL). Failure: Less than infinite resistance indicates a short to ground.

Scan Tool Commands That Help

• GDS2: Immobilizer Learn / Key Relearn — This function is used after replacing a key fob or the Body Control Module (BCM) to program new keys to the vehicle's immobilizer system. It typically involves a 10-minute or 30-minute security wait time.
• GDS2: TDM Valid Key Parameter — When diagnosing a potential bad key, this live data parameter should be monitored while turning the ignition ON with each available key. The parameter should read 'Yes' for all valid, programmed keys.

Wiring & Ground Locations

• K9 Body Control Module (BCM) — Located under the driver's side dashboard, to the far left, behind the upper kick panel and hood release lever.. The BCM is the central module for the immobilizer system. It processes the key fob signal and communicates with other modules to allow the vehicle to start. Power, ground, and communication line integrity at the BCM are critical.
• Keyless Entry Antennas — The CT6 has multiple antennas: one in the instrument panel/center of dash, one under the front of the center floor console, one in the rear trunk/fascia area, and one in each door handle.. A failure of a specific antenna can prevent the key from being detected in that zone, potentially leading to a no-start condition and setting antenna-specific DTCs. The system relies on these to locate the fob for passive entry and starting.
• Transmitter Pocket Antenna — Inside the center console storage area. The storage tray must be removed to access the pocket.. This is the backup location to start the car if the key fob battery is dead or there is significant RF interference. It uses a low-power, direct-contact antenna to read the fob's transponder chip, bypassing the normal wireless detection.

Real Owner Repair Stories

• YouTube Channel 'dallas auto diag' (2016 Cadillac CT6) — Keyless entry not working, 'Key Fob Not Detected' message, no-start condition.
  ❌ Tried (didn't work) Initial scan showed multiple communication codes., Programming keys with Autel IM608 was attempted., Checked fuses and power to the keyless entry control module.
  ✅ What actually fixed it The multi-part video series diagnoses issues with the keyless entry antennas and their wiring circuits, demonstrating live signal testing at the module connectors. The final resolution pointed towards a faulty module or wiring issue, requiring advanced electrical diagnosis beyond simple part replacement.

OEM Part Supersession History

• 13592451 → 13546098 — Part has been updated by the manufacturer.
  Heads up: The new part number (13546098) appears to be the standard replacement for various keyless entry antennas on GM vehicles from 2020-2024, but is also listed as a replacement for the earlier part.

Model Year Variations Within This Range

• 2019-2020: The 2019 model year refresh introduced a new infotainment system with a rotary controller, replacing the previous touchpad. It also featured second-generation wireless charging and a hands-free trunk with a Cadillac logo projection. While not directly tied to B3060, these electrical system changes could introduce different sources of RF interference or module interactions compared to 2016-2018 models.