Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSGMC1998ENVOY 2WD V6-4.3L VIN WREPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTCOMPUTERS AND CONTROL SYSTEMSRELAYS AND MODULES - COMPUTERS AND CONTROL SYSTEMSBODY CONTROL MODULEDESCRIPTION AND OPERATIONBODY CONTROL SYSTEM OPERATIONSERVICE PRECAUTIONS
1998 GMC Envoy 2WD V6-4.3L VIN W
Body Control System Operation: Service Precautions
1998 GMC Envoy 2WD V6-4.3L VIN WSECTION Service Precautions
Do not use a test lamp in order to diagnose the BCM electrical system unless you are specifically instructed by diagnostic procedures. Use the J 35616 when diagnostic procedures require probing of connectors. Refer to Special Tools.
The BCM will withstand normal current draws associated with vehicle operations. Avoid overloading any circuit. When testing for opens or shorts, do not ground or apply voltage to the BCM circuits unless you are instructed to do so. These circuits may only be tested using a J 39200 Digital Multimeter (DMM) or equivalent. Test electrical circuits using a J 39200 DMM, while the BCM connectors remain connected to the BCM or the recommended breakout box. Do not remove or apply voltage to the BCM when the ignition switch is in the RUN position. Turn the ignition switch to the LOCK position before removing or connecting any of the following electrical components:
^ Battery cables
^ Fuses
^ Connectors
Follow the instructions in this section whenever a BCM removal or replacement procedure is performed.
When servicing the BCM system, use the following guidelines:
^ Always DISCONNECT the brown (BRN) BCM connector FIRST.
^ Always CONNECT the brown (BRN) BCM connector LAST.
The BCM may set codes when the ignition switch is in the OFF position.
Disconnecting the electrical connectors from the BCM will set DTC(s).
The BCM may require a 20 minute (1216 second) time period in order to power down when all of the following conditions exist:
^ The ignition switch is turned to the OFF position.
^ The BCM is not receiving any active inputs.
^ The BCM does not receive any active inputs for 20 minutes.
The BCM will withstand normal current draws associated with vehicle operations. Avoid overloading any circuit. When testing for opens or shorts, do not ground or apply voltage to the BCM circuits unless you are instructed to do so. These circuits may only be tested using a J 39200 Digital Multimeter (DMM) or equivalent. Test electrical circuits using a J 39200 DMM, while the BCM connectors remain connected to the BCM or the recommended breakout box. Do not remove or apply voltage to the BCM when the ignition switch is in the RUN position. Turn the ignition switch to the LOCK position before removing or connecting any of the following electrical components:
^ Battery cables
^ Fuses
^ Connectors
Follow the instructions in this section whenever a BCM removal or replacement procedure is performed.
When servicing the BCM system, use the following guidelines:
^ Always DISCONNECT the brown (BRN) BCM connector FIRST.
^ Always CONNECT the brown (BRN) BCM connector LAST.
The BCM may set codes when the ignition switch is in the OFF position.
Disconnecting the electrical connectors from the BCM will set DTC(s).
The BCM may require a 20 minute (1216 second) time period in order to power down when all of the following conditions exist:
^ The ignition switch is turned to the OFF position.
^ The BCM is not receiving any active inputs.
^ The BCM does not receive any active inputs for 20 minutes.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.