B3055 on 2007-2014 Buick LaCrosse: Key Problems, No-Start Causes, and Fixes

What's Unique About the 2007-2014 Buick LACROSSE

The 2007-2014 LaCrosse spans two generations with different key systems, which is critical for diagnosing B3055. The 2007-2009 models use a traditional key with an embedded chip. The 2010-2014 models use a flip-style key, and a common issue, documented in GM Technical Service Bulletin PIT5030E, is the key not being fully extended, causing a poor signal and triggering this code. This simple user error can mimic a more serious component failure, making it a crucial first check on newer models.

Diagnostic Flowchart

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

Generation note: This range covers two LaCrosse generations. The 1st gen (2007-2009) uses a standard transponder key. The 2nd gen (2010-2014) uses a flip-key. A primary cause for the 2nd gen is the key not being fully locked in the open position, which does not affect the 1st gen.

Symptoms You May Notice

• Engine will not crank (no-crank)
• Engine starts and immediately stalls (start-stall)
• Security indicator light is on or flashing on the dashboard
• Message on the Driver Information Center (DIC) like 'Service Theft Deterrent System'

Most Likely Causes

1. Damaged or Faulty Key Transponder 🔴 High Probability The transponder chip inside the key head can fail from being dropped, age, or electronic failure. This is the most common point of failure in any vehicle's immobilizer system.
   How to confirm: Try starting the vehicle with a spare key. If the spare key works without issue, the original key is faulty. A technician can also use a tool to check if the key is emitting a signal.
   Typical fix: Replace the faulty key. A new key must be cut and programmed to the vehicle by a dealership or an automotive locksmith.
   Est. part cost: $75-$200
2. Flip-Key Not Fully Extended (2010-2014 Models) 🔴 High Probability A GM Technical Service Bulletin (PIT5030E) specifically calls out this issue. If the flip-key is not fully locked in the straight, open position, the transponder chip may be misaligned with the exciter coil in the ignition.
   How to confirm: Remove the key, ensure it is fully extended and locked, then re-insert it and attempt to start the engine. 🎬 See how to start your LaCrosse with a dead key fob. If the car starts, this was the cause.
   Typical fix: Ensure the key is fully extended before every use. No parts are required.
   Est. part cost: $0
3. Faulty Ignition Lock Cylinder / Exciter Module 🟡 Medium Probability The exciter module is a coil of wire around the ignition lock that energizes the key's transponder. This coil can fail, creating an open circuit and preventing it from reading any key. This component is often integrated into the ignition lock cylinder housing.
   How to confirm: If multiple known-good keys fail to start the vehicle, the exciter module is the next logical suspect. A technician can use a specialized tool to check for a signal from the coil or test the circuit for proper resistance.
   Typical fix: Replace the ignition lock cylinder housing, which contains the exciter module. 🎬 Watch: Step-by-step Buick ignition lock cylinder replacement guide. The part is often sold as a complete assembly.
   Est. part cost: $90-$150
4. Low Vehicle Battery Voltage ⚪ Low Probability Low system voltage can cause unpredictable communication errors between various modules, including the BCM and the key. While not a direct cause of B3055, it can create similar symptoms and should be ruled out.
   How to confirm: Test the battery voltage. A reading below 12.0 volts with the engine off indicates a weak battery that needs charging or replacement.
   Typical fix: Charge or replace the vehicle's 12V battery.
   Est. part cost: $150-$250

Rare But Worth Checking

• Faulty Body Control Module (BCM): The BCM is the computer that runs the theft deterrent system. While it can fail, it is far less common than a key or exciter coil failure. This should be the last item to check after all other possibilities are exhausted.
• Wiring Harness Damage: A break or short in the wiring between the exciter coil and the Body Control Module (BCM) can cause this code. This is rare but possible, especially if other electrical work has been performed recently.
• Radio Frequency (RF) Interference: As noted in GM TSB PIC5650B, strong radio frequency devices on the same keychain (like building access cards, gas station speed-pass fobs, or other remote starters) can interfere with the 125 kHz signal between the key and the exciter coil, intermittently causing a no-start and setting B3055. Removing other fobs from the keychain is a simple diagnostic step.

Diagnosis Steps

1. Check the Key (2010-2014 Models): If you have a flip-key, remove it, make sure it is fully locked in the open position, and try again.
2. Remove RF Interference: Take all other fobs, access cards, and electronic devices off your keychain. Try starting the car with only the ignition key present.
3. Try the Spare Key: Attempt to start the vehicle with all available keys. If one works, the other key(s) are faulty.
4. Check Battery Voltage: Ensure the vehicle battery is fully charged and providing at least 12.4 volts.
5. Scan for Codes: Use an OBD-II scanner capable of reading Body (B) codes to confirm B3055 is the primary active code.
6. Inspect the Ignition Cylinder: Visually inspect the ignition lock cylinder area for any signs of damage or tampering.
7. Test the Exciter Coil: A professional technician can use a diagnostic tool to verify if the exciter coil around the ignition is producing a signal. If there is no signal, the ignition lock cylinder/housing needs replacement.
8. Check Wiring: If the exciter coil signal is present, inspect the wiring between the ignition cylinder and the Body Control Module (BCM) for opens or shorts, checking for voltage and resistance against specifications.
9. Consider the BCM: If all other components and wiring are confirmed to be good, the BCM itself may be the issue. This requires advanced diagnostics and programming upon replacement.

Parts You'll Likely Need

• Transponder Ignition Key (Flip-Key, 2010-2014) (OEM #13504205, 13504200 (Standard Ignition); 13504202, 13585206 (Push-to-Start)) — This is the most common failure point. The internal chip fails, or the flip mechanism wears out causing misalignment. Different part numbers exist for standard 'turn-key' ignitions versus 'push-to-start' systems.
  Trusted brands: ACDelco, Strattec
  OEM price range: $100-$150
  Aftermarket price range: $40-$80
• Ignition Lock Cylinder Housing (OEM #25832354 (Cross-references to Dorman 924-719, though fitment for LaCrosse may vary by year)) — This part contains the exciter coil that reads the key. If the coil fails, no key will be detected. It is the second most likely part to fail. Note: Part Dorman 924-719 is listed for older GM models but cross-references to a GM number also associated with some LaCrosse years. Verify fitment before purchase.
  Trusted brands: ACDelco, Dorman
  OEM price range: $120-$180
  Aftermarket price range: $90-$150

Related Codes That Often Appear With This One

• B3060 — This code often relates to a failure in the transponder key reading circuit, directly related to B3055.
• B3935 — This code can indicate a transponder circuit malfunction, appearing alongside B3055 as part of the same system failure.

Technical Service Bulletins (TSBs) & Recalls

• PIC5650M (and later versions like PIC5650B): Mentions B3055 in relation to intermittent no crank, no start, or start stall concerns with the security light on. It importantly suggests that Radio Frequency (RF) devices on the keychain can cause interference and trigger this code.
• PIT5030E: Diagnostic tip for intermittent no-crank on 2010-2014 models, identifying the cause as the flip-key not being fully extended, which can set B3055. This TSB applies to a wide range of GM vehicles including the LaCrosse, Regal, Verano, Equinox, and Cruze.
• PIE0232: An engineering information bulletin requesting data on low-mileage 2013 trucks with B3055, B3060, or B3935, showing it's a known issue GM has actively investigated.

Platform-Specific Known Issues

• On 2010-2014 models with a flip-key, an intermittent no-crank with B3055 can be caused by the key not being fully extended and locked before insertion, as per GM TSB PIT5030E.
• A user on a Reddit forum for the Chevy Cruze, a platform mate, described a 'Service Theft Deterrent System' alert with a no-start that was ultimately resolved by a mobile locksmith who likely had to address a key or programming issue, after DIY methods like battery resets failed.