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Home >> Chevrolet >> 2007 >> Chevy Express G2500, Van Cargo Extended, 6.6 2 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System & Fuel System - 6.6L (LLY) - DTC P0016 To DTC P0341 >> DTC P0102 or P0103 >> Circuit/System Testing

Circuit/System Testing

Perform the Circuit/System Verification before proceeding with Circuit/System Testing.

  1. Ignition OFF, disconnect the harness connector at the MAF/IAT sensor.
  2. Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit terminal 4 and ground.
    • If greater than 5 ohms, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  3. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 3 and ground.
    • If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
  4. Verify the scan tool MAF parameter is less than 1 g/s.
    • If greater than 1 g/s, test the signal circuit terminal 5 for a short to voltage. If the circuit tests normal, replace the ECM.
  5. Install a 3A fused jumper wire between the signal circuit terminal 5 and the ignition circuit terminal 3. Verify the scan tool MAF parameter is greater than 500 g/s.
    • If less than 500 g/s, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
    6. IMPORTANT: Do NOT drain the coolant at this time.
  6. Remove the air inlet tube to intake manifold. Refer to Exhaust Gas Recirculation Valve Cooler Replacement . Perform steps 1-15.
  7. Visually inspect the EGR valve and verify the valve is in the closed position.
    • If the EGR valve is not in the closed position, replace the EGR valve.
    • If the EGR valve inspection is normal, replace the MAF/IAT sensor.
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