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Home >> Cadillac >> 2006 >> STS V >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - 4.4L - DTC P0506 To P2544 >> DTC P2228 or P2229 >> Circuit/System Testing
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Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the BARO sensor.
  2. Ignition OFF, allow sufficient time for the control module to power down. Measure for less than 5 ohms of resistance between the low reference circuit of the connector and a good ground.
    • If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit and ground.
    • If less than the specified range, test the 5-volt reference circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the ECM.
    • If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  4. Verify the scan tool BARO sensor voltage parameter is less than 15 kPa.
    • If greater than the specified range, tests the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  5. Install a 3A fused jumper wire between the signal circuit and the 5-volt reference circuit. Verify the scan tool BARO sensor parameter is greater than 190 kPa.
    • If less than the specified range, test the sensor signal circuit for an open/high resistance or a short to ground.
  6. If all circuits test normal, test the sensor. Refer to Component Testing.
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