Circuit/System Testing

2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6SECTION Circuit/System Testing
WARNING: This page is about a different car, the 2007 GMC Sierra and 2007 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector of the suspect rear object alarm sensor.
  2. Test for less than 1.0 ohm of resistance between the low reference circuit and ground.
    • If greater than 1.0 ohm, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the rear object alarm module.
  3. Ignition ON with the transmission in reverse, test for 8.2-8.8 volts between the rear object alarm sensor supply voltage circuit and the low reference circuit.
    • If greater than 8.8V, test the supply voltage circuit for a short to voltage. If the circuit tests normal, replace the object alarm module.
    • If less than 8.2V, test the supply voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the rear object alarm module.
  4. Ignition OFF, test for greater than 1.0 ohm of resistance between the rear object alarm sensor signal circuit and ground.
    • If less than 1.0 ohm, test the signal circuit for a short to ground. If the circuit tests normal, replace the rear object alarm module.
  5. Ignition ON, verify that a test lamp does not illuminate between the rear object alarm sensor signal circuit and ground.
    • If the test lamp illuminates, test the signal circuit for a short to voltage. If the circuit tests normal, replace the rear object alarm module.
  6. Ignition OFF, disconnect the rear object alarm module. Test for less than 1.0 ohm of resistance along the signal circuit.
    • If greater than 1.0 ohms, repair the signal circuit for an open/high resistance.
  7. If all circuits test normal, replace the suspect rear object alarm sensor.
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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.