System Description

1998 GMC Envoy 2WD V6-4.3L VIN WSECTION System Description
The BCM is designed in order to perform the following functions:
^ Process various input information
^ Send the needed electrical responses to the other control modules

The input information is related to more than one output. If one input fails, the failure may affect the operation of more than one system.

The BCM controls the operation of the following components:
^ The audible reminders
^ The warnings
^ The power door locks
^ Interior lighting
^ Exterior lighting

The BCM has features that permit the following functions:
^ Timing out and turning OFF inadvertent loads
^ Providing retained accessory power

The BCM is designed in order to interface with a Remote Function Actuator (RFA) subsystem. The interface provides remote operation of certain features of the vehicle. The BCM also provides vehicle security with an integrated Passlock system.

The BCM communicates via a Class 2 serial data bus. The communication enables diagnosis and programming at the assembly plant or an approved service center.

The BCM supplies a buffered voltage to various sensors and switches through an internal resistance in the BCM. The resistance is so high in value that an ordinary test lamp may not light when the lamp is connected to the circuit. An ordinary shop voltmeter may give an inaccurate reading because the voltmeter input impedance is too low. Use a J 39200 Digital Multimeter (DMM) in order to ensure accurate voltage readings. Refer to Special Tools.
RENDER: 1.0x

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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.