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Home >> Buick >> 2008 >> Allure CXL >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 10 (Engine Control System & Fuel System - 5.3L - DTC P0420 To DTC P3449) >> DTC P2120, P2122, P2123, P2125, P2127, P2128, or P2138 >> Circuit/System Verification

Circuit/System Verification

WARNING: This page is about a different variant/trim than selected.
  1. Ignition ON, observe the scan tool APP sensor 1 voltage parameter. The reading should be between 0.35-4.75 volts, and change with accelerator pedal input.
  2. Ignition ON, observe the scan tool APP sensors 2 voltage parameter. The reading should be between 0.35-4.75 volts and change with accelerator pedal input.
  3. Ignition ON, observe the scan tool APP sensors 1 and 2 parameter. The scan tool should indicate agree.
  4. Clear the DTCs with the scan tool. Operate the vehicle within the Conditions for Running the DTC, or within the conditions that you observed from the Freeze Frame/Failure Records.
  5. Verify that DTC P2120 or P2125 are not the only throttle position DTCs set.
    • If DTC P2120 or P2125 are the only DTCs set, replace the ECM.
  6. Verify that DTCs P0641 or P0651 are not set.
  7. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.