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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 P154B >> Circuit/System Testing

Circuit/System Testing

IMPORTANT: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
  1. Connect a test lamp between the battery positive voltage circuit terminal 1 X2 at the IAH and ground. The test lamp should illuminate.
    • If the test lamp does not illuminate, test the circuit for an open/high resistance or a short to ground and repair as necessary.
  2. Test the following circuits for an open, a short to ground, or a short to voltage:
    • The IAH command 1 circuit between terminal 31 X2 of the GPCM and terminal 2 X1 of the IAH
    • The IAH command 2 circuit between terminal 26 X2 of the GPCM and terminal 3 X1 of the IAH
    • The IAH voltage signal circuit between terminal 30 X2 of the GPCM and terminal 5 X1 of the IAH
    • If a condition was found on any of the circuits repair as necessary.
  3. Connect any circuits that were disconnected. With the ignition ON and the engine OFF, observe that the scan tool displays the IA Heater Undervoltage parameter as OK.
    • If the IA Heater Undervoltage parameter displays Fault, replace the intake air heater.
    • If the IA Heater Undervoltage parameter does not display Fault, replace the GPCM.
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