B3055 on 2007-2014 GMC Acadia: Security Light, No Start Causes & Fixes

What's Unique About the 2007-2014 Gmc ACADIA

The first-generation GMC Acadia and its Lambda platform mates use GM's Pass-Key III+ (PK3+) immobilizer system. While effective, this system's components, particularly the ignition lock cylinder which contains the reader coil (exciter), can wear over time. Furthermore, GM has issued multiple technical service bulletins for this platform highlighting that intermittent no-start conditions with a B3055 code can be caused by something as simple as radio-frequency interference from other devices on the owner's keychain (like other car fobs, office access cards, or even aftermarket LED lights). On models with a flip-key, not having the key fully extended when inserting it into the ignition can also cause this code by misaligning the transponder with the reader.

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)
• Engine starts briefly then immediately stalls
• Security warning light is solid or flashing on the instrument cluster
• A 'Service Theft Deterrent System' message may appear on the driver information center
• Horn may sound and a 'Theft Attempted' message may display when trying to start.

Most Likely Causes

1. Worn or Damaged Ignition Key 🔴 High Probability The transponder chip in the key head can fail internally, get damaged from being dropped, or the key housing can break. Over time, the key's signal can weaken, leading to intermittent detection by the vehicle.
   How to confirm: Try starting the vehicle with a spare key. If the spare key works consistently, the original key is faulty. A locksmith or dealer can also test the key's transponder signal. A technician on Reddit shared a story where a physically broken key with a B3055 code was misdiagnosed as a bad starter by the owner. 🎬 Watch: How a misleading B3055 code can mimic a bad starter.
   Typical fix: Replace the faulty key and have the new key programmed to the vehicle. This often involves a 10-minute relearn procedure that can be done with the new key.
   Est. part cost: $50-$150
2. Faulty Ignition Lock Cylinder / Switch 🟡 Medium Probability The exciter coil that reads the key's transponder is part of the ignition lock cylinder assembly. This component or its wiring can fail from wear and tear after many years of use, preventing it from energizing and reading the key. The wiring harness connected to the cylinder is also a known failure point.
   How to confirm: If a known-good key doesn't solve the problem, a technician will need to test the resistance and signal output of the exciter coil and its wiring harness leading to the BCM, as outlined in service manuals. This involves checking for B+ voltage, good ground, and signal integrity at the module connector.
   Typical fix: Replace the ignition lock cylinder and switch assembly. This may also require a key relearn procedure. Aftermarket brands like Dorman offer replacements. 🎬 See this step-by-step walkthrough for replacing the ignition switch.
   Est. part cost: $100-$250
3. Radio Frequency (RF) Interference ⚪ Low Probability As noted in GM Technical Service Bulletin PIC5650M, other RFID-enabled devices on the same keychain (like office key cards, other car keys, or gas station payment fobs) can interfere with the communication between the key and the vehicle. Aftermarket LED interior lights have also been identified as a source of RFI.
   How to confirm: Remove all other keys and electronic fobs from the Acadia's key ring. Try starting the vehicle with the key completely isolated. If it starts reliably, interference was the cause.
   Typical fix: Keep other RFID devices on a separate keychain from the vehicle key. Remove any aftermarket electronics that may be causing interference.
   Est. part cost: $0

Rare But Worth Checking

• Faulty Body Control Module (BCM): This is the least likely cause and should only be considered after all other possibilities (key, ignition switch, wiring) have been definitively ruled out. The BCM is the computer that runs the security system, and internal failure is rare but possible. On a related Buick Enclave, a heat-soaked ECM caused a no-start, showing that module failure can be intermittent.
• Damaged Wiring Harness: The wires running from the ignition lock cylinder to the Body Control Module (BCM) can become chafed, broken, or develop high resistance in the connectors. This will prevent the key signal from reaching the BCM, mimicking a faulty key or ignition switch. A diagnostic check involves testing for continuity and resistance on this harness.

Diagnosis Steps

1. Scan for all DTCs in the BCM to confirm B3055 is present and see if other related codes exist.
2. Try starting the vehicle with a known-good spare key. If it starts, the primary key is the issue.
3. Remove all other keys, fobs, and RFID cards from the keychain. Attempt to start the vehicle with only the Acadia key to rule out RF interference.
4. If you have a flip-key, ensure it is fully extended and locked in the straight position before inserting it into the ignition.
5. Inspect the ignition key for any visible damage or cracks in the plastic head.
6. If the issue persists, inspect the wiring and connector at the ignition lock cylinder for any signs of damage, corrosion, or pushed-out pins.
7. Using a multimeter, a technician can test the wiring between the ignition cylinder and the BCM. Check for less than 10 ohms of resistance on the ground circuit and B+ voltage on the power circuit. The signal circuit should have less than 2 ohms of resistance end-to-end.
8. If all wiring and components test good, the final step is to diagnose the Body Control Module (BCM) itself, which is an unlikely failure.

Parts You'll Likely Need

• Transponder Ignition Key (OEM #20873620, 20922917 (Varies by year/options)) — The internal transponder chip in the original key is the most common point of failure for this code.
  Trusted brands: ACDelco
  OEM price range: $70-$120
  Aftermarket price range: $40-$80
• Ignition Lock Cylinder with Switch (OEM #25832354 (Supersedes 15822350)) — This assembly contains the reader coil (exciter) that communicates with the key. If this coil or the switch fails, the key cannot be read, triggering B3055.
  Trusted brands: ACDelco, Standard Motor Products, Dorman (P/N: 924-719)
  OEM price range: $150-$250
  Aftermarket price range: $80-$160

Related Codes That Often Appear With This One

• B3060 — This code often relates to a failure in the transponder key reading circuit, appearing alongside B3055. TSB PIC5650M lists them together as common codes for this issue.
• B3935 — Indicates a transponder authentication error, which is a logical next step if the transponder can't be detected (B3055). This code is also mentioned in TSB PIC5650M.
• B2955 — This code indicates a malfunction in the security sensor data circuit, which can be triggered along with B3055 when the BCM has trouble communicating with the ignition cylinder components.

Technical Service Bulletins (TSBs) & Recalls

• PIC5650M (and previous versions like PIC5650B): Addresses intermittent no crank, no start, or start stall concerns with the security light on, potentially caused by RFID interference from other fobs or even aftermarket LED lights.
• PIT5030E: Notes that an intermittent no-crank with DTC B3055 can be caused by the flip-key not being fully extended, a common user-induced error.
• PIE0232: An engineering information bulletin where GM was actively investigating the root cause of B3055, B3060, and B3935 on low-mileage vehicles, indicating it was a known issue early on.

Platform-Specific Known Issues

• Per TSB #PIC5650M, these vehicles can experience an intermittent no-crank or start-stall with a B3055 code due to interference from other RFID devices on the keychain. This TSB covers a wide range of GM vehicles, including the Acadia and its platform mates.
• Per TSB #PIT5030E, models with a flip-style key can set a B3055 if the key is not fully extended and locked straight when inserted into the ignition, as this misaligns the transponder chip with the reader coil.

Hidden / Shadow Codes Worth Checking

• B3055 00: The '00' is a symptom byte indicating 'No Sub Type Information'. This means the primary code B3055 provides the full description of the fault without needing further classification. It is the most common variant seen on scan tools. (see via GM GDS2 or other professional-grade scan tools that can read manufacturer-specific symptom bytes.)

Scan Tool Commands That Help

• GDS2 (GM Techline Connect): Immobilizer Programming / Key Learning — This function is required after replacing a key, the ignition lock cylinder, or the Body Control Module (BCM). It guides the technician through the 10-minute (for adding a key) or 30-minute (for all keys lost) relearn procedure.
• GDS2 or equivalent professional scanner: BCM Data Display: 'TDM Transponder Key' or 'Key Part Number' — When diagnosing an intermittent B3055, a technician can view this live data parameter. It should display 'Present' or a valid part number when a known-good key is in the ignition. If it reads 'Not Present' or is blank, it confirms the BCM is not reading the key transponder.

Wiring & Ground Locations

• Body Control Module (BCM) — Underneath the driver's side dash panel, often to the left of the steering column. It is a black box with multiple large electrical connectors.. The BCM is the central module for the Pass-Key III+ system. All signals from the ignition lock cylinder's reader coil are sent here for validation. A poor connection at the BCM is a possible, though less common, cause of B3055.
• G300 — Behind the right kick panel, in the passenger footwell area.. This is a major interior ground point. While not directly tied to the immobilizer circuit in all diagrams, a poor ground at G300 can cause a variety of strange electrical issues with the BCM and other interior modules, potentially leading to communication errors that could manifest as a B3055.

Real Owner Repair Stories

• acadiaforum.net user (2008 GMC Acadia) — Intermittent no-start condition. Sometimes it would start, other times it would not. When it failed to start, the 'Service Theft Deterrent System' message would appear.
  ❌ Tried (didn't work) Replacing the battery in the key fob., Using the spare key (the problem occurred with both keys)., Performing the 10-minute key relearn procedure multiple times.
  ✅ What actually fixed it The owner replaced the ignition switch/lock cylinder assembly. After replacement and performing the 30-minute 'All Keys Lost' relearn procedure, the problem was permanently resolved.

OEM Part Supersession History

• 15822350 → 25832354 — Part revision and consolidation across multiple GM platforms.
  Heads up: The replacement part 25832354 requires programming/special setup procedures after installation, as described in GM service information. It is not a simple plug-and-play replacement.

Model Year Variations Within This Range

• 2013-2014: The 2013 model year introduced a significant interior and exterior facelift for the Acadia. While the underlying Pass-Key III+ system remained conceptually the same, some wiring harnesses and connector locations for the BCM and related components may differ slightly from the earlier 2007-2012 models. Technicians should always verify the correct wiring diagram for the specific model year they are working on.