Section 44 (Anti-Theft System): Operation

1998 Chevrolet Suburban K2500, 7.4 J, Part TimeSECTION Operation
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 1998 GMC Savana Special, 1998 GMC Savana Camper Special, 1998 GMC Savana, 1998 Chevrolet RV Cutaway, and 1998 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.

When mechanical key turns the PASSLOCK(R) lock cylinder, a Resistance Code (R-Code) is created by a rotating magnet turning past a stationary hall effect sensor. R-Code is sent to the PASSLOCK(R) module. The module determines the validity of the R-Code within a preset time window, then send a coded password to the Vehicle Control Module (VCM), which then allows the fuel injectors to operate normally.

If PASSLOCK(R) module receives the wrong R-Code, VCM will go into LONG TAMPER MODE. During the long tamper mode, the fuel injectors will be shut off for 10 minutes and the SECURITY indicator light will flash. Vehicle may crank and temporarily start during tamper mode, but will soon stall due to fuel shut-off.

If coded password is not received or is incorrect by the time engine starts, VCM will enter lock-out mode. If a large magnet is placed near PASSLOCK(R) sensor or a tamper (wrong key) exists, VCM will enter lock-out mode. Lack of data from PASSLOCK(R) sensor to PASSLOCK(R) module will set DTCs and illuminate SECURITY indicator light.

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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.