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Home >> Cadillac >> 2009 >> STS V >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls And Fuel - 4.4L - DTC P0010 To DTC P0158 >> DTC P012C or P012D >> Circuit/System Testing

Circuit/System Testing

NOTE: You must perform the Circuit/System Verification before proceeding with the Circuit/System Testing.
  1. Verify the integrity of the SCIAP sensor system by inspecting for the following conditions:
    • Any damage to the SCIAP sensor housing
    • A loose or improperly installed SCIAP sensor
    • A restriction in the vacuum source of the SCIAP sensor
  2. Ignition OFF, disconnect the harness connector at the SCIAP sensor.
  3. Ignition OFF for 90 seconds, test for less than 5 ohms between the low reference circuit and ground.
    • If greater than the specified range, test the low reference circuit terminal A for an open/high resistance. If the circuit tests normal, replace the ECM.
  4. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal C and ground.
    • If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
  5. Verify the scan tool SC Inlet Pressure Sensor parameter is less than 20 kPa.
    • If the greater than the specified parameter, test the signal circuit terminal B for a short to voltage. If the circuit tests normal, replace the ECM.
  6. Install a 3A fused jumper wire between the 5-volt reference circuit terminal C and the signal circuit terminal B. Verify the scan tool parameter is greater than 95 kPa.
    • If less than the specified parameter, test the signal circuit for a short to ground, open/high resistance. If the circuit tests normal, replace the ECM.
  7. If all circuits test normal, test or replace the SCIAP sensor.
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