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Home >> Hummer >> 2009 >> H3 Base, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls And Fuel - 3.7L - DTC P0324 To DTC P0446 >> DTC P0641 or P0651 >> Circuit/System Testing
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Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector of all appropriate sensors for the applicable DTC.
    2. IMPORTANT: A short to voltage on the signal circuit of certain components may cause this DTC to set.
  2. Ignition ON, measure for 4.8-5.2 volts between one of the 5-volt reference circuits and ground.
    • If the voltage is less than the specified value, test for a short to ground on all the 5-volt reference circuits. If all circuits test normal, replace the ECM.
    • If the voltage is greater than the specified value, test for a short to voltage on all the 5-volt reference circuits. If all circuits test normal, replace the ECM.
  3. Connect each component associated with the 5-volt reference circuit, one at a time, while monitoring the voltage. Verify the voltage remains between 4.8-5.2 volts.
    • If the voltage display is not within the specified range when a component is connected, test the signal circuit for a short to voltage. If all circuits test normal, replace the component.
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