B2960 on Pontiac: How to Diagnose & Fix
Key/Immobilizer Communication Error
2 Pontiac models · 2 documented issues · $100-$450 repair
B2960 on Pontiac by model: symptoms, diagnosis and fix
The G6's Passlock theft-deterrent system can falsely trip, illuminating the security light and preventing the engine from starting. The common cause is a worn ignition lock cylinder/Passlock sensor that fails to read the lock rotation correctly. The well-known 10-minute relearn trick only resets it temporarily; the fault usually returns until the cylinder/sensor is replaced.
Common Symptoms
- Car cranks but won't start
- Security/anti-theft (padlock) light on or flashing
- Intermittent no-start
- Starts after waiting ~10 minutes
How to Fix
Temporary: turn key to ON and wait ~10 minutes until the security light stops flashing (repeat the relearn cycle as needed). Permanent fix is replacing the ignition lock cylinder / Passlock sensor and relearning the system, sometimes with a fresh dealer key.
Sources for this issue (3)
The 2000-2005 Bonneville uses GM's Passlock II immobilizer, which reads a Hall-effect sensor in the ignition lock cylinder housing rather than a chip in the key. The sensor and its hair-thin wiring at the column degrade, so the BCM sees a bad or missing signal, flashes the Security lamp, and disables the fuel injectors: the engine cranks, fires for a second, then dies, or does not fire at all. It is intermittent and worse in cold weather. Owners on the Pontiac Bonneville Club and GM Forum document the 10-minute relearn ritual (key on, wait until the security light stops flashing, three cycles) as the only way to get home; the earlier 1992-1999 cars used the different PASS-Key II resistor-pellet key and are not covered by this failure mode.
Common Symptoms
- Engine starts then dies after 1-2 seconds
- Security light flashing or steadily lit with no-start
- Cranks but no fuel delivery
- Starts normally after a 10-minute key-on wait
- Intermittent, worse in cold weather
How to Fix
Temporary: perform the 10-minute Passlock relearn (three consecutive 10-minute key-on cycles). Permanent: replace the ignition lock cylinder/Passlock sensor assembly (about $100-200 in parts, plus column disassembly) and perform the relearn; inspect the yellow/black Passlock wiring at the column connector for chafing first. Many owners instead install a Passlock bypass module. No recall.
Sources for this issue (4)
B2960 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does B2960 mean on a Pontiac?
B2960 stands for "Key/Immobilizer Communication Error." B2960 is a body/security code indicating a key or immobilizer (anti-theft) communication error, where the security module read sensor or key data that appears valid in form but does not match the expected, previously learned value. On many vehicles this involves a Passlock or transponder/immobilizer check that must pass before the computer allows the engine to start. When it fails, you typically get a security/anti-theft warning light and a no-start or no-crank condition. This is a manufacturer-specific code tied to the theft-deterrent system rather than an engine mechanical fault. On Pontiac it is documented across 2 models: G6, Bonneville.
What are the most common causes of B2960?
The most common causes of B2960 are: Faulty Passlock/ignition lock cylinder sensor, Damaged or worn transponder key or key chip, Wiring or connector fault in the security sensor circuit, Body control module (BCM) failure or needs relearn, Incomplete or lost immobilizer/key relearn procedure, Worn ignition lock cylinder, Aftermarket alarm or remote-start interference. The specific cause varies by vehicle.
How much does it cost to fix B2960 on a Pontiac?
Published repair estimates on Pontiac range from $100 to $450 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for B2960 on a different make?
View B2960 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.