Component Testing

2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6SECTION Component Testing
WARNING: This page is about a different car, the 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, 2010 Chevrolet Silverado, and 2010 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT: You must perform the Circuit/System Testing in order to verify the integrity of the MAF sensor circuits before proceeding with the Component Testing.
  1. Ignition OFF, remove the MAP sensor.
  2. Install a 3A fused jumper wire between the 5-volt reference terminal C and the corresponding terminal of the MAP sensor
  3. Install a jumper wire between the low reference terminal A of the MAP sensor and ground.
  4. Install a jumper wire at the signal terminal B of the MAP sensor.
  5. Connect a DMM between the jumper wire from terminal B of the MAP sensor and ground.
  6. Ignition ON, with the J-23738-AΒ  or J-35555Β  , slowly apply vacuum to the sensor while observing the voltage on the DMM. See Special Tools . The voltage should vary between 4.9-0.02 volts, without any spikes or dropouts.
    • If the voltage is erratic, replace the MAP 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.