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Home >> Chevrolet >> 2001 >> Camaro Base, 2D Convertible, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 5 (Anti-Theft System) >> Diagnostic Tests >> DTC B2721: Pass-Key(R) Detection Circuit Out Of Range >> Diagnostic Aids

Diagnostic Aids

WARNING: This page is about a different car, the 2000 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.
  1. The following conditions may cause an intermittent:
    • Intermittent open or short to ground in White/Black wire or Purple/White wire between BCM and ignition switch.
    • Poor connections at BCM or ignition switch.
    • Incorrect PASS-Key(R).
    • Dirty or loose ignition lock cylinder key contacts or PASS-Key(R) resistor.
  2. If key resistor pellet is incorrect, there will be no BCM outputs to theft deterrent relay or PCM for about 3 minutes. If a key (even a proper PASS-Key(R)) is inserted or ignition is turned on again, a 3-minute time-out period will reset. If battery is disconnected, time-out period will be reset when battery is reconnected.
  3. Though it is unlikely, DTC B2721 may set due to extremely hot or cold ambient temperatures. To eliminate this possibility, perform tests with vehicle and key at room temperature.
  4. Clean key resistor contacts thoroughly. Check for poor connections at BCM and ignition lock cylinder. A poor connection may cause an open, an incorrect PASS-Key(R) resistance or an intermittent malfunction.
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