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Home >> Cadillac >> 2010 >> STS 3.6 V, AWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 18 (Engine Controls And Fuel - 4.6L (LH2) - DTC P0335 To DTC P2544) >> DTC P0641 or P0651 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.
NOTE: Additional DTCs may set when disconnecting components.
  1. Ignition OFF, disconnect the harness connector of all the sensors connected to the 5 V reference bus for the applicable DTC. Refer to Diagnostic Aids.
    2. NOTE: A short to voltage on the signal circuit of certain components may cause this DTC to set.
  2. Ignition ON, test for 4.8-5.2 V between one of the 5 V reference circuits and ground.
    • If less than the specified range, test all of the 5 V reference circuits for a short to ground. If all circuits test normal, replace the K20 ECM.
    • If greater than the specified range, test for a short to voltage on all of the 5 V reference circuits. If all circuits test normal, replace the K20 ECM.
  3. Connect each component associated with the 5 V reference circuit, one at a time, while monitoring the voltage. Verify the voltage remains between 4.8-5.2 V.
    • 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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