Circuit/System Testing

2008 Chevrolet Chevy Express G3500, Van Passenger ExtendedSECTION Circuit/System Testing
WARNING: This page is about a different variant/trim than selected.
  1. Using the DTC Descriptor and Diagnostic Aids determine which module is not communicating.
  2. Ignition OFF, disconnect the harness connector at the module that is not communicating.
  3. Test for less than 0.5 ohm between each ground circuit of the module that is not communicating and ground.
    • If greater than 0.5 ohm, repair the open/high resistance in the ground circuit.
  4. Test for battery voltage between each battery positive voltage circuit of the module that is not communicating and ground.
    • If less than battery voltage, repair the short to ground or open/high resistance in the battery positive voltage circuit.
  5. Ignition ON, test for battery voltage between each ignition circuit of the module that is not communicating and ground.
    • If less than battery voltage, repair the short to ground or open/high resistance in the ignition circuit.
  6. Ignition OFF, disconnect the harness connector at the module that reported the no communication DTC.
  7. Ignition OFF, test for less than 0.5 ohm in each serial data circuit between the module that is not communicating and the module that reported the DTC.
    • If greater than 0.5 ohm, repair the open/high resistance in the serial data circuit.
  8. If all tests normal, replace the module that is not communicating.
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.