Diagnostic Aids

1999 Chevrolet Cutaway 7.4 JSECTION Diagnostic Aids

Prior to replacing a Passlock™ module ensure all the diagnostics have been performed. With an existing system condition, the replacement Passlock™ module will not learn a new voltage code (DTC B3031) until the original condition has been repaired.

Perform a visual inspection of the wiring and the connectors. Inspect the Passlock™ sensor harness for an intermittent or poor connections (including the in-line connector).

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:

  • 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.