What Does B2722 Mean?
B2722 indicates a fault in the PASS-Key (Passive Anti-theft System) detection circuit, which is part of the vehicle's security system. The Body Control Module (BCM) or security module has detected an abnormal signal or lack of signal from the transponder key recognition system. This prevents the BCM from properly identifying authorized keys, which may result in a no-start condition or intermittent starting issues.
Safety Warning
Vehicle may not start or may experience intermittent no-start conditions, leaving you stranded. While not a direct safety hazard if the vehicle runs, the inability to reliably start the vehicle creates a safety concern in emergency situations or unfamiliar locations.
Common Causes
35%
Faulty or damaged transponder key with weak or failed chip signal
30%
Defective ignition lock cylinder with damaged antenna coil or poor electrical connection
20%
Wiring harness damage or corroded connections between ignition cylinder antenna and BCM
15%
Failed Body Control Module or security module with internal circuit fault
Diagnostic Steps
1
Step 1: Attempt to start vehicle with all available keys to determine if fault is key-specific or system-wide. Document which keys work or fail, and observe security light behavior during key-on and crank attempts.
2
Step 2: Visually inspect the ignition lock cylinder area for physical damage, debris, or moisture. Check the transponder antenna ring around the cylinder for cracks, displacement, or loose mounting.
3
Step 3: Using a multimeter, measure resistance across the transponder antenna coil terminals (typically 2-10 ohms depending on vehicle). Inspect wiring harness from ignition cylinder to BCM for chafing, breaks, or corrosion at connectors.
4
Step 4: If available, use advanced scan tool to monitor PASS-Key module data stream for transponder signal strength and key resistance values during key insertion. Compare readings to manufacturer specifications (typically 400-11,800 ohms range depending on key code).
5
Step 5: Test a known-good transponder key if available. If problem persists with all keys, focus on antenna coil and BCM connections. If one key works, inspect failed key chip for damage or perform key relearn procedure.
6
Step 6: After repair, perform security system relearn procedure as specified by manufacturer (typically 10-minute key-on cycles). Clear codes and verify no-start condition is resolved and security light functions normally.
Estimated Repair Cost
$85 - $650
Parts + labor, varies by vehicle and location
B2722 indicates a fault in the PASS-Key (Passive Anti-theft System) detection circuit, which is part of the vehicle's security system. The Body Control Module (BCM) or security module has detected an abnormal signal or lack of signal from the transponder key recognition system. This prevents the BCM...
The most common cause of B2722 (PASS-Key Detection Circuit) is: Faulty or damaged transponder key with weak or failed chip signal
Typical repair costs for B2722 range from $85 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle may not start or may experience intermittent no-start conditions, leaving you stranded. While not a direct safety hazard if the vehicle runs, the inability to reliably start the vehicle creates a safety concern in emergency situations or unfamiliar locations.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B2722 to identify the root cause.
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Quick Info
Category
Body
System
Vehicle Security System / Anti-Theft System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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