B3055 on 2007-2010 Pontiac G5: No-Start, Security Light Causes and Fixes

What's Unique About the 2007-2010 Pontiac G5

The Pontiac G5 shares its core platform (GM Delta) with the Chevrolet Cobalt, and both are well-known for experiencing this specific anti-theft system issue. The problem is so common that GM has issued multiple technical service bulletins regarding intermittent no-start conditions related to the security system. These bulletins often point towards external factors like radio frequency interference or issues with flip-style keys before blaming component failure. The ignition lock cylinder itself was also the subject of a customer satisfaction program (TSB #10256) for the 2009 model year due to binding issues, highlighting the mechanical stresses on this component.

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 or start.
• Engine starts and then immediately stalls.
• Security indicator light (often a car with a lock symbol) is on solid or flashing on the dashboard.
• A 'Theft System' or similar message may appear on the driver information center.
• Key may be difficult to turn or gets stuck in the ignition cylinder, which can be a related mechanical failure.

Most Likely Causes

1. Radio Frequency Interference (RFI) 🔴 High Probability GM TSB PIC5650M specifically calls out that the Passkey system, which operates at 125 kHz, is sensitive to interference from other RFID devices on the keychain or even aftermarket electronics inside the car like phone chargers.
   How to confirm: Remove all other keys (especially for other cars), key fobs, and RFID-enabled cards (like office access cards) from the keychain. Try starting the vehicle with the single, isolated Pontiac key. If it starts, RFI was the cause.
   Typical fix: Keep other RFID devices separate from the ignition key when starting the vehicle. Remove low-quality aftermarket chargers or devices from the 12V outlets.
   Est. part cost: $0
2. Faulty or Damaged Ignition Key 🔴 High Probability → Shop Ignition Switch The transponder chip embedded in the plastic head of the key can be damaged if the key is dropped, exposed to water, or if the plastic housing is cracked. The chip itself can also fail electronically with age.
   How to confirm: Try starting the vehicle with a known-good spare key. If the spare key works consistently, the original key is faulty. This is the single most effective diagnostic step.
   Typical fix: The faulty key must be replaced. A new key needs to be cut and then programmed to the vehicle. This can be done via a 30-minute relearn procedure or by a dealer/automotive locksmith.
   Est. part cost: $50-$150
3. Lost Key Programming / Security System Glitch 🟡 Medium Probability A low battery, jump-starting, or a voltage spike can sometimes cause the Body Control Module (BCM) to lose its memory of the learned keys, triggering a security event. Sometimes this can happen for no apparent reason.
   How to confirm: Attempt the 30-minute manual key relearn procedure. If this procedure is successful and the car starts, the issue was lost programming.
   Typical fix: Perform the 30-minute key relearn procedure: Turn the key to 'ON' (do not start) and wait about 10-11 minutes until the security light goes out. Turn the key 'OFF' for 10 seconds. Repeat this two more times for a total of three cycles. After the third cycle, the key should be relearned, and the car should start.
   Est. part cost: $0
4. Faulty Ignition Lock Cylinder / Passlock Sensor 🟡 Medium Probability → Shop Ignition Switch The exciter coil (antenna) that reads the key's transponder is part of the ignition lock cylinder assembly. The thin wires leading to this coil can fatigue and break from the repeated rotational stress of turning the key, causing an open circuit. This component is a known weak point and was subject to a GM Customer Satisfaction Program (#10256) for the 2009 model year for related binding issues.
   How to confirm: If multiple known-good keys fail to start the car and the relearn procedure does not work, the lock cylinder assembly is the most likely hardware failure. Wiggling the key in the ignition may cause it to work intermittently, pointing to a broken wire.
   Typical fix: Replace the ignition lock cylinder assembly. After replacement, the 30-minute key relearn procedure must be performed. Common aftermarket parts like the Dorman 924-719 are available.
   Est. part cost: $60-$130

Rare But Worth Checking

• Failing Body Control Module (BCM): → Shop Body Control Module While less common, the BCM itself can fail. This is often a last resort after all other possibilities (key, interference, lock cylinder) have been ruled out. A failed BCM will often set other trouble codes as well and may be caused by water intrusion.
• Damaged Wiring: The wires running from the ignition lock cylinder to the BCM can become damaged or develop a poor connection, though this is less common than component failure. On the related Chevy Cobalt, corroded ground wires near the fuse box or transmission have been found to cause a no-crank condition that can be misdiagnosed.
• Stuck Ignition Key Interlock: → Shop Ignition Switch After a dead battery, the key can become physically stuck in the ignition. This is not a B3055 fault, but can happen at the same time. There is a small access panel under the steering column where a white button can be pressed to manually release the key.

Diagnosis Steps

1. Scan the Body Control Module (BCM) for codes to confirm B3055 is active.
2. Observe the security light on the dashboard. Note if it's flashing or solid.
3. Remove all other keys, fobs, and RFID cards from the keychain and try to start the car again to rule out RFI.
4. If available, try starting the vehicle with a known-good spare key. If it works, the primary key is the issue.
5. Attempt the 30-minute manual key relearn procedure.
6. If the relearn fails and spare keys do not work, inspect the wiring and connector at the ignition lock cylinder for any visible damage.
7. If wiring is intact, the next logical step is to replace the ignition lock cylinder assembly. This often requires removing the steering column covers. After replacement, perform the relearn procedure again.
8. If the problem persists, the Body Control Module (BCM) may be faulty and requires professional diagnosis with a high-end scan tool.

Parts You'll Likely Need

• Ignition Lock Cylinder (OEM #25807440) — This assembly contains the Passlock sensor (exciter coil/transceiver) that reads the key's transponder. It is a common failure point that prevents the key from being detected. This part is also listed as an 'Anti-Theft Control Module' in some catalogs.
  Trusted brands: ACDelco, Dorman (p/n 924-719 for some applications)
  OEM price range: $60-$110
  Aftermarket price range: $40-$80
• Transponder Ignition Key (OEM #GM P/N: 15826824, Key Blank: B111-PT) — The chip inside the key can fail from damage or age, making it unreadable by the vehicle's security system.
  Trusted brands: ACDelco, Strattec
  OEM price range: $40-$80
  Aftermarket price range: $20-$50

Related Codes That Often Appear With This One

• B3060 — This code for 'Unidentified Key' can appear with B3055. The system may first fail to detect a key (B3055) and then, on a subsequent attempt, get a partial read but not recognize it (B3060).
• B3935 — This code for 'Transponder Authentication Error' is also related to the security handshake between the key and the car and is frequently mentioned in the same TSBs as B3055.

Technical Service Bulletins (TSBs) & Recalls

• PIC5650M: Addresses intermittent no crank, no start, or start stall concerns with the security light on, specifically mentioning DTC B3055 and the potential for

Platform-Specific Known Issues

• A Technical Service Bulletin (TSB #PIC5650M) was issued by GM for an intermittent no-crank, no-start, or start-stall condition with the security light on, which specifically lists B3055 as a potential code. It advises checking for Radio Frequency Interference from other devices on the keychain before replacing parts.
• A Customer Satisfaction Program bulletin (#10256) was issued for 2009 Pontiac G5 models for a binding condition in the ignition lock cylinder. This can cause the key to get stuck or be hard to turn, and while not a direct cause of B3055, it shows the high mechanical stress on the component that can lead to related electronic failures.

Mechanic-Grade Diagnostic Values

• Ignition Lock Cylinder Exciter Coil Resistance — expected: 5-15 Ohms. Failure: A reading of infinite resistance (open circuit) or very high resistance indicates a failed coil.
• BCM Ground Circuit Resistance — expected: Less than 1.0 Ohm. Failure: Resistance greater than 1.0 Ohm indicates a poor ground connection or a problem in the wiring harness.

Scan Tool Commands That Help

• GM Tech2 / Professional Scan Tool: Immobilizer Data Stream — Use this function to monitor the 'TDM Transponder Key' parameter. When turning the ignition ON with a key, the parameter should read 'Present'. If it reads 'Not Present' or 'No Key Detected', it confirms the BCM is not receiving the signal from the key/transceiver.

Wiring & Ground Locations

• BCM (Body Control Module) — In the passenger footwell, located on the side of the center console, often behind a removable trim panel.. The BCM is the central module that receives and interprets the signal from the ignition key's transponder via the lock cylinder's transceiver. All related wiring terminates here.
• BCM Ground (G203 on some diagrams) — A common ground point for the BCM and other interior electronics is located behind the right side of the dashboard.. A poor ground connection to the BCM can cause a wide range of intermittent electrical issues, including the failure to correctly read the Passkey III+ signal, leading to a B3055 code.
• BCM Connector C4, Pin D3 — On the Body Control Module connector C4.. This pin carries the Yellow wire for the Passkey system signal on the Pontiac G5.
• BCM Connector C2, Pin 62 — On the Body Control Module connector C2.. This pin carries the White/Black stripe wire which is also part of the Passlock/Passkey system wiring.

Real Owner Repair Stories

• Reddit user N_dixon in r/Justrolledintotheshop (Unknown Year GM Vehicle (likely Cobalt/G5 family based on symptoms)) — No-start, towed in. DIC showed 'Theft Attempted'. Horn would go off when key was inserted. Code B3055 was active.
  ❌ Tried (didn't work) Customer believed the starter was bad.
  ✅ What actually fixed it The technician identified the B3055 code pointing to the key. The vehicle battery was also low (10.5V). After replacing the failed battery and having the customer bring a new, correct key, the technician programmed the new key to the vehicle. The car then started and ran normally, confirming the fix was a combination of a bad key and a low battery preventing proper system operation and programming.

OEM Part Supersession History

• 15778671 → 25807440 — Part revision or manufacturer change for the Theft Deterrent Module / Ignition Lock Cylinder Housing.
  Heads up: Part number 25807440 is the current replacement for the 2007-2010 Pontiac G5. It also replaces part number 22719734. This part requires programming (key relearn) after installation.