DTC B2957: PASS-Key(R) II DETECTION CIRCUIT (SHORT TO GROUND): Description

1999 Buick Regal LSSECTION 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, Body Control Module (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 B2957 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 B2957 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 B2957 will also clear when conditions no longer exist or scan tool is used to clear codes.

NOTE: If DTC B2957 is a history code, problem may be intermittent. Wiggle wires and key while performing the following test.
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.