Scan Tool Diagnosis

1998 GMC Envoy 2WD V6-4.3L VIN WSECTION Scan Tool Diagnosis
Use the scan tool in order to monitor the communications between the BCM and the PCM/VCM. The scan tool also displays Passlock data. The Passlock data list display is located under the PASSLOCK selection. This list shows the status of the hardwired connections from the Passlock sensor to the BCM. These scan tool values may be very useful in diagnosing the Passlock system.

The Passlock system is designed in order to deter theft, even if various parts are changed. The following components may not be changed without the possibility of going into no-start condition:
^ The Passlock sensor
^ The Powertrain Control Module (PCM)
^ The Body Control Module (BCM)
^ The Vehicle Control Module (VCM)

If any of these parts are replaced, refer to the Learn Procedure in BCM Programming/RPO Configuration. The BCM and the PCM/VCM require the full 10 minutes in order to complete a lockout cycle. The ignition key MUST remain in the RUN position until the telltale turns to the OFF position. If the ignition key is turned from the RUN position before the telltale turns to the OFF position, you will have to repeat the lockout cycle. The Passlock system requires 3 consecutive lockout cycles in order to complete the 30 minute learn procedure for a changed component. Refer to Theft Deterrent Diagnostic System Check for more information on the Passlock system.
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.