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Home >> Chevrolet >> 2009 >> Chevy Express G2500, Van Cargo Extended, 6.6 6 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System & Fuel System - 6.6L LMM - DTC P1224 To DTC P2463 >> DTC P154D >> Circuit/System Testing

Circuit/System Testing

IMPORTANT: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
  1. Ignition OFF, disconnect the X1 harness connector of the IAH.
  2. Turn ON the ignition and measure between temperature signal circuit terminal 1 of the connector and a good ground for 2-3 volts.
    • If greater than the specified range, test the temperature signal circuit for a short to voltage. If the circuit tests normal, replace the GPCM.
    • If less than the specified range, test the temperature signal circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the GPCM.
  3. If the temperature signal circuit tests normal, replace the IAH.
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