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Home >> Cadillac >> 2006 >> STS V >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - 4.4L - DTC P0010 To P0175 >> DTC P012C or P012D >> Circuit/System Testing
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Circuit/System Testing

  1. With the ignition OFF, disconnect the harness connector at the SCIAP sensor.
    2. IMPORTANT:
    • The test lamp is used to load the circuit and may not illuminate.
    • The SCIAP sensor 5-volt reference circuit is spliced to other components of the vehicle.
  2. With the ignition ON and the engine OFF, connect a test lamp between the SCIAP sensor 5-volt reference circuit and a good ground. With a DMM, measure for a voltage range of 4.8-5.2 volts, from the SCIAP sensor 5-volt reference circuit to a ground.
    • If the voltage is less than the specified range, test the circuit for an open, high resistance, or a short to ground. If the SCIAP sensor 5-volt reference circuit and connections tests normal, replace the ECM.
    • If the voltage is more than the specified range, test the circuit for a short to voltage. If the SCIAP sensor 5-volt reference circuit tests normal, replace the ECM.
  3. With the SCIAP sensor harness connector still disconnected, observe the SCIAP Sensor parameter for a value of less than 12 kPa with a scan tool.
    • If the SCIAP Sensor parameter is more than 12 kPa, test the SCIAP sensor signal circuit for a short to voltage. If the SCIAP sensor signal circuit tests normal, replace the ECM.
  4. Connect a 3-amp fused jumper wire between the SCIAP sensor 5-volt reference circuit and the signal circuit of the SCIAP sensor and verify the SCIAP sensor parameter is more than 103 kPa.
    • If the SCIAP Sensor parameter is less than 103 kPa, test the SCIAP sensor signal circuit for an open, high resistance, or a short to ground. If the SCIAP sensor signal circuit tests normal, replace the ECM.
  5. Turn OFF the ignition, and all electrical accessories. Allow sufficient time for the control module to power down before taking a resistance measurement. Measure for a value of less than 5 ohms of resistance between the low reference circuit of the SCIAP sensor and a ground.
    • If the resistance is more than 5 ohms, test the circuit for an open or high resistance. If the SCIAP sensor low reference circuit tests normal, replace the ECM.
    • If the SCIAP sensor circuits test normal, replace the SCIAP sensor.
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