Component Testing

2008 Chevrolet Chevy Express G3500, Van Passenger ExtendedSECTION Component Testing
WARNING: This page is about a different variant/trim than selected.
IMPORTANT: You must perform the Circuit/System Testing in order to verify the integrity of the exhaust differential pressure sensor circuits before proceeding with Component Testing.
  1. Ignition OFF, remove the exhaust pressure differential pressure sensor.
  2. Install a 3A fused jumper wire between the 5-volt reference circuit terminal 3 and the corresponding terminal of the differential sensor. Install a jumper wire between the low reference terminal 1 of the sensor and ground.
  3. Install a jumper wire between the low reference circuit terminal 1 of the differential sensor and ground.
  4. Install a jumper wire at terminal 2 of the differential sensor.
  5. Connect a DMM between the jumper wire from terminal 2 of the differential sensor and ground.
  6. Ignition ON, with the J 23738-AΒ  or J 35555Β  connected to the pressure sensor rear pressure port, slowly apply vacuum to the sensor while monitoring the voltage between the signal terminal 2 and the low reference terminal 1. See Special Tools . The voltage should vary between 4.8-0.4 volts without any spikes or dropouts.
    • If the voltage is erratic, replace the differential sensor.
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:

  • 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.