LEMON Manuals: Even more car manuals for everyone
Home >> Buick >> 1998 >> Century Custom >> Repair and Diagnosis >> Body & Frame >> Body, Cab Control Systems >> Body Control Module >> Diagnostic Tests >> DTC B2722: Pass-Key(R) II Detection Circuit (Short To Ground) >> Description

DTC B2722: Pass-Key(R) II Detection Circuit (Short To Ground): Description

PASS-Key(R) II detection circuit is completed when PASS-Key(R) II (with embedded resistor pellet) is inserted in ignition lock cylinder. When contacts in lock cylinder mate with contacts of resistor pellet, key detection circuit through circuits No. 1073 (White/Black wire) and No. 1074 (Purple/White wire) is completed.

When ignition switch is turned from LOCK/OFF position to RUN position, BCM applies a 5-volt reference voltage to circuit No. 1073 (White/Black wire). BCM then reads resistor pellet code, and compares stored resistor pellet code with ignition key resistor pellet code to verify a correct match. If BCM determines that resistance value of key pellet is okay, BCM will use the class 2 serial data line to send an enable password to Powertrain Control Module (PCM). PCM will then energize theft deterrent relay and allow fuel delivery to engine.

DTC B2722 will set when voltage level of PASS-Key(R) input circuit No. 1073 (White/Black wire) is low (indicating invalid resistance detected or a short to ground) during crank cycle or for one second anytime after engine has been started.

When DTC B2722 is set, BCM will send a message to instrument panel to turn on SECURITY warning indicator. If DTC is set during crank cycle, BCM will not send a message to PCM to enable theft deterrent relay and allow fuel delivery to engine (vehicle will exhibit a "no crank" condition). If DTC occurs later in ignition cycle, BCM will enter fail-enable mode. During subsequent engine starts, BCM will send a message to PCM to enable theft deterrent relay and to allow fuel delivery to engine.

If conditions for malfunction no longer exist, history DTC will clear after 100 consecutive ignition cycles. DTC B2722 will also clear when conditions no longer exist or scan tool is used to clear codes.

NOTE: If DTC B2722 is a history code, problem may be intermittent. Wiggle wires and key while performing the following test.
NOTE: When ignition switch is turned to RUN position with BCM disconnected, PCM-related DTC P1626 will be set. After BCM repair is completed, see appropriate TESTS W/CODES article in ENGINE PERFORMANCE section:
scientia non olet · About LEMON Manuals