B3055 on 2007-2010 GMC Sierra 2500: No-Start, Security Light Causes and Fixes

What's Unique About the 2007-2010 Gmc SIERRA 2500

The GMT900 platform, which includes the 2007-2010 Sierra, uses GM's Passkey III+ immobilizer system. This system is known for being sensitive to interference and having issues with the components in and around the steering column. GM has issued several revisions of a service bulletin (PIC5650B, C, K, M) related to intermittent no-start conditions and this specific code. These bulletins highlight interference from aftermarket devices like USB chargers, LED lights, and toll passes as a primary diagnostic path before part replacement.

Diagnostic Flowchart

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

Symptoms You May Notice

• Vehicle will not crank or start
• Engine starts and then immediately stalls
• Security indicator light is solid or flashing on the dashboard
• "Service Theft Deterrent System" message may appear on the Driver Information Center (DIC)
• Key may feel gritty or become difficult to turn in the ignition prior to complete failure.

Most Likely Causes

1. Defective or Damaged Ignition Key 🔴 High Probability The transponder chip embedded in the key head can be damaged from drops or wear over time. The flip-key design can also cause issues if not fully extended when inserted into the ignition.
   How to confirm: Try starting the vehicle with a spare key. If the spare key works reliably, the original key is faulty.
   Typical fix: Replace the faulty key. A new key must be cut and programmed to the vehicle.
   Est. part cost: $50-$150
2. Radio Frequency (RFID) Interference 🔴 High Probability The Passkey system operates on a low-frequency (125 kHz) signal that is easily disrupted by other RFID-enabled items or aftermarket electronics.
   How to confirm: Remove all other keys, fobs, access cards, and speed passes from the keychain. Also unplug any aftermarket USB chargers or phone holders and turn off aftermarket LED lights. Try starting the vehicle with the ignition key completely isolated.
   Typical fix: Keep the ignition key on its own ring or separate from other RFID devices when starting the vehicle. Remove low-quality aftermarket electronics.
   Est. part cost: $0
3. Faulty Ignition Lock Cylinder Housing (Passlock Sensor/Antenna) 🟡 Medium Probability The sensor (exciter coil/antenna) that reads the key's transponder is part of the ignition lock cylinder housing. The thin wires leading to the antenna coil can fatigue and break from the repeated rotational stress of turning the key, causing an open circuit. This is a very common failure point discussed in owner forums.
   How to confirm: After ruling out the key and interference, a technician can use a scan tool to monitor the transponder key data. 🎬 See how to perform professional GM Passlock diagnostics. If the data is absent or erratic ('Not Present') even with a known-good key, the sensor/housing is the prime suspect.
   Typical fix: Replace the ignition lock cylinder housing. This repair requires a security relearn procedure. The OEM part is GM #20869121 and a common aftermarket replacement is Dorman 924-719.
   Est. part cost: $70-$200
4. Damaged Wiring or Poor Connection ⚪ Low Probability The wiring from the lock cylinder to the BCM can become chafed or damaged within the steering column, or the connector can become loose, though this is less common than the housing itself failing.
   How to confirm: Visually inspect the wiring harness for damage. Perform a continuity and resistance test on the signal, power, and ground wires between the lock cylinder connector and the BCM.
   Typical fix: Repair the damaged section of wire or re-secure the connector.
   Est. part cost: $5-$50

Rare But Worth Checking

• Failing Body Control Module (BCM): This is the least likely cause and should only be considered after all other possibilities (key, sensor, wiring) have been thoroughly tested and ruled out. BCM replacement is expensive and requires programming by a dealer or qualified shop.

Diagnosis Steps

1. Scan for all DTCs in the BCM and other modules. Note any other security-related codes like B3060 or B3935.
2. Inspect the ignition key for any physical damage. Try starting the vehicle with a known-good spare key.
3. Remove all other keys, fobs, and RFID cards from the keychain. Unplug any aftermarket devices (phone chargers, etc.). Attempt to start the vehicle with only the single ignition key present, as recommended by TSB PIC5650M.
4. If using a flip-key, ensure it is fully extended and locked straight before inserting it into the ignition.
5. Attempt the manual 30-minute security relearn procedure. 🎬 Watch: Step-by-step guide to the GM security relearn procedure. First, ensure the battery is fully charged or connected to a battery charger. Turn the key to 'ON' (do not start) and wait approximately 10-11 minutes until the security light on the dash turns off. Turn the key OFF for 10 seconds. Repeat this process two more times (three 10-minute cycles total). After the third cycle, turn the key off, then attempt to start the engine.
6. If the issue persists, inspect the wiring and connector at the base of the ignition lock cylinder 🎬 Watch this video to find a common no-crank wiring fix. for any visible damage or looseness.
7. Using a professional scan tool, monitor the 'Transponder Key' status in the Theft Deterrent Module data. If it reads 'Not Present' with a known-good key, the ignition lock cylinder housing/sensor is the most likely cause.
8. If all the above steps fail, the Body Control Module (BCM) may be at fault, which requires advanced diagnostics.

Parts You'll Likely Need

• Ignition Lock Cylinder Housing (OEM #20869121) — This housing contains the Passlock sensor (exciter coil/antenna) that reads the key. It is the most common hardware failure for this code after the key and RFI have been ruled out. The internal wires are a known weak point.
  Trusted brands: ACDelco, GM Genuine Parts, Dorman 924-719
  OEM price range: $150-$220
  Aftermarket price range: $70-$120
• Transponder Ignition Key (OEM #25925281) — The chip inside the key can fail, making it unrecognizable to the vehicle. This is a common and simple fix if a spare key works.
  Trusted brands: ACDelco, Strattec 5913441
  OEM price range: $70-$120
  Aftermarket price range: $40-$80

Related Codes That Often Appear With This One

• B3060 — This code, 'Unlearned Key Detected,' often appears with B3055 as they both relate to the BCM not recognizing the key signal.
• B3935 — This code relates to 'Transponder Authentication Failed' and is another part of the same Passkey system handshake failure.

Technical Service Bulletins (TSBs) & Recalls

• PIC5650M / PIC5650K / PIC5650C / PIC5650B: Addresses intermittent no crank/no start/stall with security light on, listing B3055. The multiple revisions highlight the ongoing and difficult-to-diagnose nature of Radio Frequency Interference (RFI) from sources like other keys, toll passes, and aftermarket electronics like LED lights and phone chargers.
• PIT5030E: Notes that an intermittent no-crank with DTC B3055 can be caused by the flip-key not being fully extended when inserted into the ignition.

Platform-Specific Known Issues

• A GM Technical Service Bulletin (PIC5650 and its many revisions like M and K) directly addresses code B3055 causing an intermittent no-crank or start-stall condition. It specifically calls out checking for RFID devices and aftermarket electronics (USB chargers, LED lights) as a primary diagnostic step before replacing parts.
• Another bulletin (PIT5030E) notes that on vehicles with flip-keys, not having the key fully extended can cause a poor reading and set code B3055.
• Owner experiences shared on forums like gm-trucks.com confirm that replacing the ignition lock cylinder housing is the definitive fix for many who experience recurring B3055 issues that are not resolved by the 30-minute relearn or removing RFI sources. This points to the eventual mechanical failure of the antenna wiring within the housing.

Mechanic-Grade Diagnostic Values

• Scan Tool TDM 'Transponder Key' Parameter — expected: Present. Failure: Parameter reads 'Not Present' when a known-good key is in the ignition.

Scan Tool Commands That Help

• Tech 2 / GDS2: View Data -> Theft Deterrent Module (TDM) -> Transponder Key Status — Use this to verify if the TDM is electronically 'seeing' the transponder chip in the key. If the status is 'Not Present' with a good key, it points to a faulty antenna/reader coil in the ignition lock cylinder housing.
• Tech 2 / GDS2: Service Programming System (SPS) -> Programming Theft Deterrent System Components / Add Key — This function is required after replacing the ignition lock cylinder housing (TDM) or adding a new key to make the vehicle learn and accept the new component's security signature.

Wiring & Ground Locations

• Body Control Module (BCM) — Located behind the driver-side lower dashboard panel, near the steering column and interior fuse block.. The BCM is the gateway for the theft deterrent system; it communicates with the TDM and ECM to allow the engine to start. A poor connection or faulty BCM can cause this code. A GM bulletin warns that the BCM can be damaged if its ground path is removed while battery power is connected.
• BCM Ground Path — For 2007 models, the BCM ground path runs through the Left Instrument Panel Junction Block.. A poor ground connection here can cause intermittent BCM operation and security system faults. Per GM bulletin 07-08-47-004D, the negative battery cable MUST be disconnected before servicing this junction block or any BCM ground to prevent damaging the module.

Real Owner Repair Stories

• Reddit r/Justrolledintotheshop (GM Vehicle (specific model not stated, but behavior is identical)) — No-start, towed in. Key blade was broken and fob was damaged. DIC showed 'Theft Attempted' message.
  ❌ Tried (didn't work) Owner assumed it was the starter motor.
  ✅ What actually fixed it The technician diagnosed DTC B3055 and also found the battery was failing at 10.5V. The final fix required replacing the battery to ensure stable voltage, and then programming a new, undamaged key to the vehicle.

OEM Part Supersession History

• Multiple (e.g., 15282624, 15825311, 19177419, 25848835) → 20869121 — This part has undergone numerous revisions to address failures. The current part number, 20869121, replaces a long list of previous numbers.
  Heads up: No known incompatibilities; 20869121 is the correct service replacement for the earlier parts.